You can have a good credit score, a steady job, money saved for a down payment—and still find that your debt-to-income ratio becomes one of the most important numbers in your mortgage approval.

DTI is one of the primary ways lenders compare your monthly financial obligations with the income being used to qualify for the mortgage.

But it’s also one of the most misunderstood parts of the mortgage pre-approval process.

Homebuyers often ask questions like:

• What debt actually counts?
• Is there a maximum debt-to-income ratio?
• Does a car payment hurt more than a credit-card balance?
• How are student loans treated?
• Does the new mortgage payment count in the calculation?
• Can paying off a debt help you qualify for more?
• What if part of your income comes from overtime, bonuses, or commissions?

Understanding how DTI works can give you a much clearer idea of why you qualify for a certain mortgage amount—and what might be possible if your current ratio is too high.

What Is a Debt-to-Income Ratio?

Your debt-to-income ratio compares your total monthly debt obligations with the stable monthly income the lender is using to qualify you.

For mortgage purposes, the calculation generally looks like this:

Total monthly debt obligations ÷ qualifying monthly income = debt-to-income ratio

For example, suppose a borrower has:

Qualifying monthly income: $8,000

And monthly obligations of:

• Proposed housing payment: $2,500
• Auto loan: $500
• Student loan: $300
• Credit cards: $200

Total monthly obligations would be $3,500.

$3,500 ÷ $8,000 = 43.75% debt-to-income ratio

That doesn’t automatically tell us whether the borrower will or won’t qualify.

It gives the lender one important piece of the overall mortgage analysis.

For Fannie Mae, DTI is formally defined as the borrower’s total monthly obligations—including the housing expense—divided by stable monthly income.

Does Your New Mortgage Payment Count in Your DTI?

Yes.

This is one of the most important things for homebuyers to understand.

When determining your mortgage DTI, the lender doesn’t look only at the debts you already have.

The proposed housing expense for the home you’re buying is part of the calculation too.

That housing expense can include more than just principal and interest.

Depending on the transaction, the monthly housing payment may include items such as:

• Principal
• Interest
• Property taxes
• Homeowners insurance
• Mortgage insurance
• HOA dues when applicable

That’s one reason a mortgage calculator that only shows principal and interest can create an overly optimistic picture of affordability.

For Michigan homebuyers, property taxes can be especially important because the taxes you ultimately pay after purchasing a home may not be the same as the seller’s current tax bill.

A higher realistic housing payment means a higher DTI.

What Debts Are Usually Included in a Mortgage DTI?

Mortgage guidelines don’t simply add up every bill that leaves your checking account.

They focus on specific financial obligations that need to be considered when evaluating your ability to repay the mortgage.

For conventional financing, that can include obligations such as:

• Auto loans
• Student loans
• Credit-card minimum payments
• Personal loans
• Other mortgages
• Certain alimony or child-support obligations
• Lease payments
• Other recurring debts required under the applicable guidelines

Fannie Mae’s current guidance requires lenders to consider liabilities that affect the borrower’s income, assets, or ability to make the mortgage payment, including revolving accounts and many installment debts.

What does not necessarily happen is the lender counting every monthly household expense.

Things like groceries, utilities, cell-phone bills, streaming services, and normal living expenses aren’t typically entered into the mortgage DTI calculation in the same way as installment or revolving debt.

That doesn’t mean those expenses don’t matter to your personal budget.

It simply means mortgage qualification and personal affordability aren’t exactly the same thing.

What Is a Good Debt-to-Income Ratio for a Mortgage?

There isn’t one universal DTI number that guarantees mortgage approval.

The allowable ratio can depend on:

• Loan program
• Automated underwriting findings
• Credit profile
• Assets and reserves
• Down payment
• Property and transaction characteristics
• Whether the loan is manually underwritten
• Other risk factors in the file

This is where online advice like:

“Your DTI has to be below 43%.”

can become misleading.

Different mortgage programs and underwriting methods can allow different ratios.

For example, current Fannie Mae guidance says manually underwritten loans generally have a maximum total DTI of 36%, which can increase to 45% when applicable credit-score and reserve requirements are met. Loans evaluated through Fannie Mae’s Desktop Underwriter can allow a DTI of up to 50%.

That doesn’t mean everyone with a 49.9% DTI will be approved.

And it doesn’t mean someone at 40% automatically has a stronger loan than someone at 44%.

DTI is one part of the entire credit and underwriting picture.

Front-End Ratio vs. Back-End Ratio

You may also hear mortgage professionals talk about a front-end ratio and a back-end ratio.

The front-end ratio generally compares the proposed housing expense with your qualifying income.

The back-end—or total DTI—includes the proposed housing expense plus your other monthly debt obligations.

For example:

Monthly income: $8,000
Housing payment: $2,400

Front-end housing ratio:

$2,400 ÷ $8,000 = 30%

Now add:

• $500 auto payment
• $250 student loan
• $150 credit-card payments

Total debts become:

$3,300

Total DTI:

$3,300 ÷ $8,000 = 41.25%

For many modern mortgage approvals, the total DTI is the ratio borrowers hear about most often, but the housing expense can still matter depending on the loan program and underwriting method.

Why Two People With the Same Income Can Qualify for Very Different Mortgage Amounts

This is where DTI becomes much easier to understand.

Imagine two Michigan homebuyers who each earn $100,000 per year.

That works out to roughly $8,333 per month before considering the specifics of qualifying income.

Buyer A

• No auto loan
• $100 credit-card minimum payment
• No student loan payment

Existing monthly debt: $100

Buyer B

• $750 auto payment
• $400 student loan payment
• $250 credit-card payments

Existing monthly debt: $1,400

Both buyers earn the same income.

But Buyer B already has $1,300 more in monthly obligations before the proposed mortgage payment is added.

That can create a substantial difference in mortgage buying power.

This is why annual salary alone doesn’t tell you how much home you can qualify to purchase.

Your income matters.

What you’re already obligated to pay each month matters too.

Qualifying Income Matters Just as Much as the Debt

DTI has two sides.

Borrowers often focus only on reducing debt, but the denominator in the calculation—your qualifying income—is equally important.

This becomes especially relevant when part of your earnings comes from overtime, bonus, or commission income.

If a lender can use additional variable income for qualification, your DTI could decrease even though your debts haven’t changed.

If some of that income cannot be used, your DTI could be higher than you expected.

That’s why a thorough mortgage pre-approval should involve calculating both sides correctly:

What monthly obligations must be counted?

and

What income can actually be used?

A mistake on either side can produce the wrong mortgage qualification.

How Are Credit Card Payments Calculated in Your DTI?

Credit cards are one of the most common debts included in a mortgage debt-to-income ratio.

But lenders generally don’t divide your credit-card balance by a certain number of months or assume you need to pay the entire balance immediately.

For a revolving account, the required monthly payment is what generally matters for DTI.

Suppose you have:

Credit-card balance: $6,000
Minimum monthly payment: $175

The $175 payment—not the entire $6,000 balance—is generally the number relevant to your monthly debt obligations.

What if the credit report shows a balance but doesn’t report a minimum payment?

For Fannie Mae conventional financing, if there isn’t documentation supporting a lower payment, the lender generally must use 5% of the outstanding balance. For a loan run through Desktop Underwriter, DU will use the greater of $10 or 5% of the outstanding balance when a revolving debt is entered without a monthly payment.

That can produce a surprisingly large qualifying payment.

For example:

$10,000 balance × 5% = $500 per month

That’s another reason it’s important for your mortgage pre-approval to be based on an actual review of your credit and liabilities rather than a rough online estimate.

Do Credit Cards With a Zero Balance Count Against Your DTI?

Generally, a revolving account with no required monthly payment isn’t creating a recurring monthly debt payment simply because the account is open.

You don’t necessarily need to close unused credit cards to qualify for a mortgage.

In fact, making major changes to your credit accounts immediately before or during the mortgage process isn’t something I’d recommend doing without discussing it with your mortgage professional first.

Your credit score and your DTI are related to different parts of mortgage qualification.

Paying down a credit-card balance could potentially lower the monthly obligation used in your DTI, depending on the resulting required payment, while also affecting your credit utilization.

But closing the account is an entirely separate decision.

How Are Auto Loans and Personal Loans Treated?

Auto loans and personal loans are generally considered installment debt.

For Fannie Mae conventional financing, installment debts such as automobile loans and personal loans generally must be included in recurring monthly obligations when more than 10 monthly payments remain.

What if only a few payments are left?

This is another area where the common advice gets oversimplified.

An installment debt with 10 or fewer remaining payments may still need to be considered if the payment significantly affects the borrower’s ability to meet their other credit obligations.

So don’t automatically assume:

“I only have nine car payments left, so the lender has to ignore it.”

The circumstances still matter.

What About a Car Lease?

A vehicle lease is treated differently from an auto loan with only a few payments remaining.

Under current Fannie Mae guidance, lease payments are considered recurring monthly obligations regardless of how many months remain on the lease.

Why?

Because when a vehicle lease expires, most borrowers will still need transportation. They may enter another lease, purchase the existing vehicle, or finance another vehicle.

So if you have three months left on a $600-per-month auto lease, don’t assume that $600 automatically disappears from the mortgage calculation because the lease is almost over.

This can be particularly important for borrowers with expensive vehicle leases because the monthly payment can have a meaningful effect on DTI.

How Are Student Loans Calculated in Your DTI?

Student loans deserve their own discussion because the qualifying payment isn’t always as straightforward as what’s shown on a credit report.

For Fannie Mae conventional financing, if the credit report shows a monthly student-loan payment, the lender may generally use that amount.

If the credit report doesn’t reflect the correct payment, the lender may use the payment shown on the borrower’s most recent student-loan documentation.

But what if the credit report shows $0, or no monthly payment at all?

Current Fannie Mae guidance provides different treatment depending on the situation.

If the borrower is on an income-driven repayment plan and documentation verifies the actual monthly payment is $0, the lender may qualify the borrower using a $0 payment.

For deferred student loans or loans in forbearance, the lender may instead use either:

• 1% of the outstanding student-loan balance, or
• A fully amortizing payment based on the documented repayment terms.

That distinction can have a substantial effect on DTI.

Someone with $50,000 in student loans could have a very different mortgage calculation depending on the applicable payment treatment.

That’s why homebuyers with education debt shouldn’t assume that having student loans automatically prevents them from buying a home.

The actual student loan payment used for mortgage qualification is what matters.

What If Someone Else Pays One of Your Debts?

Here’s a scenario we see fairly often:

Your name is on an auto loan, but your spouse, parent, child, or another person has actually been making the payments.

Does the debt still have to count against you?

Not necessarily.

For certain non-mortgage debts, Fannie Mae allows the lender to exclude a payment from the borrower’s recurring monthly obligations when another party has actually been making the payments and the applicable documentation requirements are satisfied.

Generally, the lender needs evidence showing the other party made the most recent 12 months of payments with no delinquent payments. The other person doesn’t necessarily have to be legally obligated on the non-mortgage debt, although an interested party to the subject transaction cannot be the person used to establish the exclusion.

This can make a significant difference.

Imagine you cosigned an auto loan with a $700 monthly payment for your adult child.

If you’ve never actually made the payments and the appropriate history can be documented, there may be circumstances where that $700 payment doesn’t have to be included in your DTI.

That’s much different from simply telling the lender:

“Don’t worry, my son pays that.”

Documentation matters.

What If Someone Else Pays a Mortgage That’s in Your Name?

Mortgage debt has additional requirements.

For Fannie Mae conventional financing, when another party is making payments on a mortgage obligation, the full housing expense may potentially be excluded from the borrower’s recurring obligations if specific requirements are met.

Among those requirements, the person making the payments must also be obligated on the mortgage debt, and there can be no delinquencies during the most recent 12 months. The borrower also cannot use rental income from that property to qualify while simultaneously using this particular exclusion.

This is another example of why debt-to-income calculations can become more nuanced than simply adding every account appearing on a credit report.

Does Child Support or Alimony Count in DTI?

Certain court-ordered obligations can count.

Under current Fannie Mae guidance, required child support, alimony, equalization payments, or separate maintenance that will continue for more than 10 months generally must be considered in the mortgage qualification.

For certain obligations, including alimony, Fannie Mae also provides an option to reduce qualifying income rather than treating the obligation as a monthly debt. Child support does not receive that same income-reduction option.

Either way, these obligations need to be disclosed and properly evaluated.

Does an IRS Payment Plan Count as Debt?

It can.

If you’re repaying delinquent federal income taxes through an IRS installment agreement and aren’t paying the balance in full, the monthly installment payment generally needs to be included in your recurring monthly obligations when the applicable Fannie Mae requirements are met.

The lender will need documentation of the agreement and evidence regarding its status.

Having an IRS payment plan doesn’t automatically mean you can’t qualify for a mortgage.

But ignoring the payment when estimating your DTI can give you an inaccurate picture of your buying power.

Does a HELOC Payment Count Against Your DTI?

A home equity line of credit, or HELOC, can also affect your DTI.

If the HELOC requires a monthly principal-and-interest or interest-only payment, Fannie Mae requires that payment to be considered as part of the borrower’s recurring monthly obligations.

If the HELOC doesn’t require a payment, Fannie Mae does not require the lender to create an equivalent monthly obligation simply because the line exists.

This becomes particularly important for homeowners trying to buy another home before selling their current property.

Using home equity can provide funds for a down payment, but borrowing against that equity may also create an additional monthly obligation that needs to be considered when qualifying for the new mortgage.

Does a Bridge Loan Affect Your DTI?

Potentially, yes.

A bridge loan can help a homeowner access equity from their current property to purchase another home before the existing home sells.

But borrowing the money can create an additional obligation.

Under Fannie Mae guidelines, the resulting bridge-loan liability generally must be considered in the borrower’s recurring monthly obligations.

However, Fannie Mae provides an exception when the current residence has a fully executed sales contract and the applicable financing contingencies have been cleared.

This is another reason buy-before-you-sell transactions need to be structured carefully.

It’s not enough to determine whether you have sufficient equity.

You also need to determine how the existing home, new mortgage, and any financing used to access that equity affect your qualification.

What About a 401(k) Loan?

This one surprises a lot of homebuyers.

A loan secured by certain financial assets—such as a 401(k), IRA, life-insurance policy, stocks, bonds, or similar assets—doesn’t necessarily have to be included as a recurring monthly debt when the applicable documentation requirements are satisfied.

Fannie Mae treats these differently because the borrower is borrowing against their own financial asset.

However, if you’re also trying to use that same asset to satisfy mortgage reserve requirements, the value of the asset generally needs to be reduced by the outstanding loan proceeds and related fees when determining the available reserves.

So a $400 monthly 401(k) loan payment shouldn’t automatically be treated the same way as a $400 unsecured personal loan.

Again, what kind of debt you have matters—not just the payment amount.

Why Reviewing Your Actual Debts Before House Shopping Matters

By now, you can probably see why calculating DTI from memory isn’t always reliable.

A borrower might say:

“I have a car payment, two credit cards and a student loan.”

But mortgage qualification may require us to ask:

How many payments remain on the car?

Is it a loan or a lease?

What minimum payments are reporting on the credit cards?

What payment is being used for the student loan?

Does someone else actually pay one of these debts?

Are there other obligations that aren’t appearing on the credit report?

Do you have another property?

Do you have a HELOC?

Those details can change the calculation.

A strong mortgage pre-approval isn’t just about pulling a credit score and entering your annual salary.

It’s about understanding the complete financial picture before determining what mortgage payment and purchase price your finances can support.

Can Paying Off Debt Help You Qualify for a Mortgage?

Yes—and sometimes the effect can be significant.

Because DTI is based on monthly obligations, eliminating a monthly payment can potentially improve your ratio and increase the mortgage payment you can qualify for.

Suppose you have:

Qualifying monthly income: $8,000
Existing monthly debts: $1,200
Proposed housing payment: $2,400

Your total monthly obligations would be:

$3,600

That produces a DTI of:

45%

Now suppose $500 of the existing debt is an auto loan that can legitimately be excluded because it will be paid off.

Your monthly obligations could drop to:

$3,100

Your DTI would then be:

38.75%

Nothing changed about your income.

Nothing changed about the house.

Eliminating one $500 monthly obligation reduced the DTI by more than six percentage points.

That’s why paying off the right debt can sometimes have a much greater impact on mortgage qualification than borrowers expect.

Should You Pay Off Debt Before Getting Pre-Approved?

Not necessarily.

This is where strategy matters.

If you have $15,000 available, you might assume the smartest move is to immediately pay off as much debt as possible before applying for a mortgage.

But that same $15,000 might also be needed for:

• Your down payment
• Closing costs
• Prepaid expenses
• Escrow funding
• Financial reserves
• Moving expenses
• Emergency savings after closing

Using all of your available cash to eliminate debt could improve your DTI while creating a different problem: not having enough money to complete the transaction or maintain adequate reserves.

That’s why I generally wouldn’t recommend making large debt payoffs specifically for mortgage qualification until the entire financial picture has been reviewed.

Sometimes paying off a $300 monthly obligation is extremely helpful.

Sometimes it isn’t necessary at all.

And sometimes preserving the cash is more valuable than eliminating the payment.

A proper mortgage pre-approval lets you determine whether a debt actually needs to be addressed before you start moving money around.

Can Debt Be Paid Off at Closing?

In some situations, yes.

For Fannie Mae conventional financing, installment loans paid off—or paid down to 10 or fewer remaining monthly payments—generally don’t have to be included as long-term debt, subject to the overall analysis.

Revolving accounts can also potentially be paid off at or before closing so the existing monthly payment doesn’t have to be included in the DTI. Fannie Mae does not require the revolving account to be closed simply because it is being paid off for qualification.

That can create useful options when a borrower is close to qualifying.

For example, imagine a buyer has enough funds for the down payment and closing costs plus additional savings.

The loan works except for a $250 monthly credit-card payment pushing the DTI slightly too high.

Rather than assuming the borrower needs to purchase a less expensive home, it may be worth determining whether paying off that account is an appropriate solution.

The key is to make that decision as part of the mortgage analysis—not randomly before the lender has reviewed the file.

Which Debt Should You Pay Off First to Improve DTI?

If the objective is specifically to improve mortgage DTI, the largest balance isn’t necessarily the most important debt.

The monthly payment is what matters most.

Consider:

Debt A

Balance: $12,000
Monthly payment: $225

Debt B

Balance: $4,000
Monthly payment: $300

If both debts could appropriately be eliminated, paying off the smaller $4,000 balance would actually create a larger immediate reduction in monthly DTI.

This is different from deciding which debt you should pay first for general personal-finance purposes.

For mortgage qualification, we’re asking:

How much monthly obligation can potentially be eliminated for the amount of cash required?

That can make debt-payoff strategy very different from simply attacking the largest balance.

Can Paying Down a Credit Card Improve Your DTI?

Potentially, but this requires a little more thought.

Remember that revolving debt is generally evaluated using the required monthly payment.

So simply reducing a credit-card balance doesn’t automatically guarantee a specific reduction in DTI.

If paying down the account causes the required minimum payment to fall, that could help.

If the account is being paid off at or before closing and qualifies to be excluded under the applicable guidelines, the effect can be more straightforward.

There can also be a separate credit benefit to reducing revolving balances because lower credit utilization may affect your credit score.

But credit score optimization and DTI optimization aren’t exactly the same thing.

One strategy may help both.

Another might improve one without significantly affecting the other.

That’s another reason to review the mortgage first.

Can You Just Add a Co-Borrower to Lower Your DTI?

Sometimes adding another borrower can help, but it isn’t as simple as adding their income.

When another borrower is added to the mortgage, the lender generally evaluates both their qualifying income and their applicable debts.

Suppose you earn:

$6,000 per month

and a co-borrower earns:

$4,000 per month

Adding that income could bring total qualifying income to $10,000 per month.

That sounds great.

But suppose the co-borrower also has:

• $700 auto payment
• $500 student-loan payment
• $300 credit-card payments

You’ve added $4,000 of income—but you’ve also added $1,500 of monthly debt.

Whether that improves the overall qualification depends on the complete calculation.

A co-borrower with strong income and relatively little debt could substantially help.

A co-borrower with significant obligations may help much less than expected.

Does Your Spouse’s Debt Count If They Aren’t on the Mortgage?

This is one of those questions where the loan program and applicable state/property rules matter.

You shouldn’t assume that leaving a spouse off the mortgage automatically means every obligation associated with that spouse becomes irrelevant.

Different mortgage programs can have different requirements regarding a non-borrowing spouse and debts.

This is particularly important when comparing FHA and Conventional loans, because government and conventional underwriting rules aren’t always identical.

If you’re married but planning to apply for the mortgage using only one spouse’s income and credit, tell your mortgage professional early so the loan can be structured and evaluated correctly.

Can Higher Income Fix a High DTI?

Potentially.

Remember the formula:

Monthly obligations ÷ qualifying monthly income = DTI

Reducing the numerator—your debts—can lower the ratio.

Increasing the denominator—your usable qualifying income—can also lower it.

Suppose your monthly obligations total:

$4,000

Using $8,000 of qualifying income:

$4,000 ÷ $8,000 = 50% DTI

Using $9,000 of qualifying income:

$4,000 ÷ $9,000 = 44.44% DTI

That’s a substantial difference without eliminating a single debt.

But the important phrase is qualifying income.

You can’t simply tell the lender you expect to make more money next year and have that projected amount inserted into the calculation.

Mortgage underwriting generally needs stable, documented income that meets the applicable requirements. Fannie Mae describes stable and predictable income as foundational to underwriting and requires lenders to document an acceptable history and reasonable expectation that qualifying income will continue.

This is especially important when your compensation includes overtime, bonuses, or commission income.

Those earnings may help your DTI significantly—but only to the extent they can actually be used as qualifying income.

Can a Raise Help Your DTI?

Yes, if the increased income can be properly documented and used for qualification.

Suppose your salary increases from:

$72,000 to $84,000 per year

Your gross monthly base income increases from:

$6,000 to $7,000

If the new salary satisfies the applicable income requirements, that additional $1,000 of monthly qualifying income could materially improve your DTI.

That’s different from being told you might receive more overtime or commissions in the future.

Fixed base income and variable income can require different analysis.

The important thing isn’t simply whether your paycheck has increased.

It’s whether the lender can use the increased amount when underwriting the mortgage.

What If You’re Self-Employed?

DTI still matters for self-employed borrowers.

The biggest difference is often determining the income side of the equation.

A business owner may say:

“My company made $150,000 last year.”

That doesn’t necessarily mean the lender enters $12,500 per month as qualifying income.

Self-employment income can require analysis of tax returns, business structure, expenses, ownership percentage, income trends and other factors.

Business debt can also require special treatment. For example, Fannie Mae notes that business debt for which the borrower is personally obligated generally must be considered unless applicable requirements allow it to be excluded from the borrower’s personal DTI.

So for a self-employed borrower, accurately determining DTI can require more work on both sides of the equation.

Can You Have a High DTI and Still Get Approved?

Potentially.

A higher DTI does not automatically mean the mortgage will be denied.

For Fannie Mae loans evaluated through Desktop Underwriter, the maximum allowable DTI can be as high as 50%, while manually underwritten loans generally have lower limits.

But this is where I would strongly caution against treating 50% as a target.

An automated underwriting system evaluates more than one number.

Your credit profile, assets, reserves, down payment, loan characteristics and other factors can influence the overall underwriting result.

Two borrowers with identical DTIs don’t necessarily receive identical underwriting findings.

And qualifying for a payment doesn’t automatically mean you should spend that much every month.

Maximum Approval vs. Comfortable Payment

This may be the most important distinction in the entire DTI discussion.

A lender’s job is to determine whether your mortgage satisfies the applicable underwriting requirements.

Your job is also to determine whether the payment fits your life.

Mortgage DTI doesn’t necessarily include every expense you have.

Maybe you spend significant money each month on:

• Childcare
• Health expenses
• Travel
• Hobbies
• Private-school tuition
• Helping family members
• Retirement savings
• Home maintenance
• Pets
• Entertainment

Those expenses may be very real even though they aren’t all treated as mortgage liabilities.

So if you’re approved for a $3,500 housing payment but you know that payment would make you uncomfortable every month, you don’t have to spend up to the maximum approval.

A good mortgage conversation shouldn’t simply answer:

“What’s the most house I can possibly qualify for?”

It should also help you understand:

“What payment am I comfortable carrying?”

Those numbers don’t have to be the same.

Why DTI Can Change During the Mortgage Process

Your debt-to-income ratio isn’t necessarily frozen the day you’re pre-approved.

If your income or liabilities change before closing, the lender may need to update the calculation.

For example, Fannie Mae requires the DTI to be recalculated when additional liabilities are disclosed or discovered after the underwriting decision and before or at closing.

That’s one reason borrowers are repeatedly told not to make major financial changes while buying a home.

Opening a new credit account, financing furniture, purchasing a vehicle, or taking on another loan could create a new monthly obligation.

Even if your credit score barely changes, the new payment itself could increase your DTI.

And if the revised DTI no longer satisfies the underwriting requirements, that purchase could create a mortgage problem at exactly the wrong time.

This is why the advice to avoid new debt before closing isn’t just a generic mortgage warning.

There’s math behind it.

Does the Mortgage Program Affect Your Debt-to-Income Ratio?

Yes.

There isn’t one universal DTI limit that applies to every mortgage.

A borrower’s acceptable debt-to-income ratio can depend on the mortgage program, how the loan is underwritten, and the overall strength of the application.

That’s one reason someone shouldn’t assume:

“My DTI is 46%, so I can’t get a mortgage.”

The answer may depend on whether you’re considering a Conventional loan, FHA loan, VA loan, USDA loan, or another financing option.

It can also depend on whether the loan receives an automated underwriting approval or requires manual underwriting.

The mortgage program matters.

What Is the Maximum DTI for a Conventional Loan?

For conventional mortgages following Fannie Mae guidelines, the answer depends heavily on how the loan is underwritten.

For a manually underwritten Fannie Mae loan, the maximum total DTI is generally 36%.

That can potentially increase to 45% when the borrower satisfies applicable credit-score and reserve requirements.

Loans evaluated through Fannie Mae’s automated underwriting system, Desktop Underwriter, can potentially have a DTI as high as 50%.

That doesn’t mean 50% is automatically acceptable.

It means the automated underwriting system can potentially approve a loan with a DTI up to that level after evaluating the overall application.

So when someone asks:

“What’s the maximum DTI for a Conventional loan?”

the most accurate answer isn’t simply one number.

It depends on the loan and underwriting method.

What About FHA Loans?

FHA loans also evaluate the relationship between a borrower’s income and monthly obligations, but FHA loans follow their own underwriting requirements.

An FHA borrower shouldn’t assume the Conventional loan DTI rules apply to their mortgage.

The overall loan profile and underwriting findings matter.

This is another reason FHA vs. Conventional shouldn’t be compared based only on down payment or mortgage insurance.

For a borrower whose DTI is near the qualification limit, the way different mortgage programs evaluate the complete file can become an important part of determining which option makes sense.

HUD maintains its Single Family Housing Policy Handbook 4000.1 as the comprehensive source of FHA Single Family policy, including underwriting requirements.

Why Automated Underwriting Matters

Modern mortgage approvals generally involve much more than someone looking at your DTI and comparing it with a chart.

For many loans, the application is evaluated through an automated underwriting system.

For Fannie Mae loans, that system is commonly Desktop Underwriter, often referred to as DU.

The system evaluates numerous pieces of the mortgage application together.

That means two borrowers with the same DTI don’t necessarily receive the same result.

Imagine:

Borrower A

• 47% DTI
• Strong credit history
• Significant reserves
• Stable employment and income
• Strong overall loan profile

Borrower B

• 47% DTI
• Weaker credit profile
• Minimal remaining assets
• Recent income instability
• Other risk factors

The DTI is identical.

The overall mortgage applications are not.

That’s why looking at DTI in isolation can be misleading.

Example: How a Car Payment Can Affect Buying Power

Let’s look at a simplified example.

Suppose a borrower has:

Qualifying monthly income: $9,000
Other monthly debts: $500

Now suppose the borrower is considering a home with a total proposed housing payment of:

$3,400 per month

Total obligations:

$3,900

DTI:

43.33%

Now add a recently financed vehicle with a:

$750 monthly payment

Total obligations become:

$4,650

DTI becomes:

51.67%

The borrower earns exactly the same income.

The house costs exactly the same amount.

But one additional monthly obligation dramatically changed the mortgage qualification.

This is why buying a new vehicle shortly before purchasing a home can create a problem.

It’s not simply about whether the credit inquiry lowers your credit score.

The new monthly payment can be the bigger issue.

Example: How Overtime Income Can Affect DTI

Now let’s look at the other side of the equation.

Suppose a borrower has:

Base qualifying income: $6,000 per month
Total monthly obligations: $2,900

Using only base income:

$2,900 ÷ $6,000 = 48.33% DTI

But suppose the borrower also regularly earns overtime, and after reviewing the history and documentation, the lender determines that an additional:

$750 per month

can be used as qualifying income.

Total qualifying income becomes:

$6,750

Now:

$2,900 ÷ $6,750 = 42.96% DTI

The borrower didn’t pay off any debt.

The mortgage payment didn’t change.

Accurately calculating the borrower’s overtime, bonus, or commission income changed the DTI substantially.

That’s why determining qualifying income correctly is every bit as important as identifying the correct debts.

Example: Paying Off the Right Debt

Suppose another borrower has:

Monthly qualifying income: $7,500
Total monthly obligations: $3,600

DTI:

48%

The borrower has $10,000 available beyond the funds needed for the home purchase.

They have two debts:

Credit Card A

Balance: $9,000
Payment: $200

Auto Loan B

Balance: $4,500
Payment: $450

If the applicable mortgage guidelines allow the auto obligation to be eliminated through payoff, using $4,500 to eliminate the $450 monthly payment could have a much greater DTI impact than using $9,000 to eliminate the $200 payment.

Remove the $450 obligation:

New monthly obligations: $3,150

$3,150 ÷ $7,500 = 42% DTI

That’s why I wouldn’t recommend randomly paying down debt before getting pre-approved.

Sometimes which debt you pay off matters much more than how much total debt you eliminate.

Fannie Mae specifically allows certain installment and revolving obligations paid off or appropriately paid down at or before closing to be excluded from long-term DTI, while also requiring the lender to consider whether a payoff done solely for qualification makes sense within the overall credit analysis.

Can You Calculate Your Own Mortgage DTI?

You can certainly estimate it.

Start with your gross monthly qualifying income and identify your monthly debt obligations.

Then add an estimate of the complete housing payment for the home you’re considering.

The basic formula is:

Proposed housing payment + monthly debts ÷ gross qualifying monthly income

But there are two major places where a DIY calculation can go wrong.

1. Using the Wrong Debt Payments

You may not know exactly how the mortgage program will treat:

• Student loans
• Installment debts with only a few payments remaining
• Leases
• Debts paid by someone else
• Other real estate
• HELOCs
• Bridge loans
• Court-ordered obligations
• IRS installment agreements

2. Using the Wrong Income

Your current gross earnings aren’t necessarily identical to your qualifying income.

That can become especially important with:

• Overtime
• Bonuses
• Commissions
• Variable hourly income
• Second jobs
• Seasonal employment
• Self-employment income

So an online mortgage calculator can help you estimate a payment, and you can estimate your own DTI, but neither replaces an actual mortgage review.

What Should You Do If Your DTI Is Too High?

A high DTI doesn’t necessarily mean your home-buying plans are over.

There may be several things worth evaluating.

Depending on your circumstances, possibilities could include:

• Paying off or restructuring an appropriate debt
• Choosing a lower purchase price
• Increasing the down payment when it meaningfully changes the payment
• Reviewing whether all eligible qualifying income has been included
• Comparing mortgage programs
• Addressing inaccurate liabilities appearing on your credit report
• Documenting debts that may qualify to be excluded
• Waiting until a particular financial obligation is eliminated
• Adding an appropriate co-borrower when it actually improves the overall application

The right solution depends on why the DTI is high.

If the problem is a $700 car payment, the strategy might be completely different from a borrower whose income hasn’t been calculated correctly.

This is another reason mortgage qualification shouldn’t simply be reduced to:

Approved or denied.

Sometimes the more useful question is:

“What would need to change for this loan to work?”

What Should You Avoid Doing Before Closing?

Once you’re under contract and your mortgage is being processed, avoiding unnecessary financial changes becomes particularly important.

Don’t assume you’re safe to take on new debt simply because you’ve already received a pre-approval.

Before closing, you should generally discuss significant financial changes with your mortgage professional, particularly before:

• Financing a vehicle
• Opening a new credit card
• Financing furniture or appliances
• Taking out a personal loan
• Co-signing for someone else’s debt
• Changing employment or compensation
• Moving large amounts of money without keeping documentation

A new liability discovered before closing can require the lender to recalculate DTI.

Fannie Mae specifically requires recalculation when additional liabilities are disclosed or discovered after underwriting and before or at closing.

So that “zero-interest furniture financing” for your new house might not feel like a big deal.

To mortgage underwriting, the resulting monthly payment might be very relevant.

DTI Is Important—but It Isn’t the Whole Mortgage Approval

Debt-to-income ratio matters.

But it isn’t the only thing that matters.

A complete mortgage application can involve:

• Income
• Employment
• Credit history
• Credit score
• Assets
• Down payment
• Financial reserves
• Property type
• Appraisal
• Loan program
• Other underwriting requirements

That’s why a borrower shouldn’t necessarily celebrate because an online DTI calculator says 35%.

And they shouldn’t necessarily panic because it says 47%.

The calculation needs to be accurate, and then it needs to be evaluated within the context of the actual mortgage program.

Mortgage Qualification and Affordability Are Not the Same Thing

It’s worth repeating this because it’s important.

The maximum mortgage you qualify for isn’t necessarily the mortgage you should take.

A lender’s DTI calculation doesn’t know how much you like to travel.

It doesn’t know that you want to save aggressively for retirement.

It doesn’t know that you spend heavily on childcare, hobbies, pets, or helping family members.

Mortgage underwriting determines whether a loan satisfies lending requirements.

Your personal budget determines whether the payment fits the life you want to live.

Those two numbers can be different.

A good mortgage pre-approval should give you enough information to make that decision intelligently.

The Bottom Line

Your debt-to-income ratio is one of the most important numbers used when qualifying for a mortgage, but it’s also more nuanced than simply adding up your bills and dividing by your salary.

The lender needs to determine:

• Which debts must be included
• Which debts may potentially be excluded
• The correct monthly payment for each obligation
• Your actual qualifying income
• Your proposed complete housing payment
• The requirements of the mortgage program
• The overall strength of the application

For Fannie Mae conventional loans, manually underwritten mortgages generally have a maximum total DTI of 36%, potentially increasing to 45% when applicable requirements are met, while Desktop Underwriter can allow ratios up to 50%. Those are underwriting limits—not recommendations for how much of your income you should personally spend on housing.

And something as simple as paying off the right obligation can sometimes materially change the calculation. Fannie Mae’s current guidance allows qualifying treatment for certain debts paid off or paid down at or before closing, but the lender still evaluates that strategy within the overall loan analysis.

If you’re planning to buy a home in Michigan, don’t assume your DTI is too high—or that you’re safely below the limit—based on an online calculation.

Have the numbers reviewed before you start making offers.

Want to Know What Your DTI Looks Like for a Mortgage?

BrightSide Lending can review your income, monthly obligations, credit profile, and available mortgage options to help determine what you may qualify for before you begin house shopping.

Whether you’re dealing with student loans, car payments, credit-card debt, variable income, or simply trying to determine a comfortable home-buying budget, understanding the numbers upfront can make the mortgage process much easier.

Get pre-approved today and find out what your home-buying options look like.