What Actually Counts in Your Debt-to-Income Ratio

Most of the "am I going to qualify?" conversations I have come down to one number: debt-to-income ratio. Credit score gets all the attention, but DTI is usually the thing that decides how much house you can buy, and it's the number people guess wrong most often.

The good news is that the math is simple. The confusing part is which debts count, which ones get ignored, and how a lender decides what income they can actually use. Let me walk through it the way I'd explain it at a kitchen table in Methuen or Haverhill.

The basic formula

DTI compares your monthly debt payments to your gross monthly income (before taxes). Two versions get quoted:

• Front-end ratio: just the new housing payment divided by income.
• Back-end ratio: housing payment plus all other monthly debt payments, divided by income.

The back-end number is the one that matters for almost every loan today. If you earn $9,000 a month gross and your total monthly obligations including the new mortgage would be $4,050, you're at 45%.

Where the ceiling sits depends on the program and on the rest of your file. Conventional loans run through Fannie Mae's or Freddie Mac's automated underwriting, which will generally go to 45% and can stretch to 50% when there are strong offsetting factors like reserves in the bank or a big down payment. FHA can approve above 50% in some cases when the automated findings support it. VA loans work differently and lean on residual income, which is the actual dollars left over each month after your bills. The Consumer Financial Protection Bureau has a good primer on why lenders look at this at all.

Nobody should treat those percentages as promises. They're the outer edges of what the automated systems will accept, and getting there usually requires the rest of the picture to be clean.

The housing payment includes more than principal and interest

This is where buyers in our market get surprised. Your "housing payment" for DTI purposes is the full monthly cost, often written as PITIA:

Taxes swing a lot around here. A Lynnfield property tax bill and a Lawrence property tax bill on the same loan amount can differ by hundreds of dollars a month, and that difference eats straight into your qualifying power. Same with condo fees. I've seen buyers in Lynn and Haverhill get pre-approved on a target price, then fall in love with a unit carrying a $550 monthly fee and lose $70,000 of buying power in the process. The fee counts dollar for dollar in your ratio, whether or not it includes heat.

If you're shopping condos, ask for the fee amount early and tell your loan officer. It changes the answer.

Which debts count

We pull your credit report and use the minimum monthly payments listed there. Not what you actually pay, the minimum.

Counts:

• Car loans and leases (a lease counts even if it ends in four months)
• Student loans, with some nuance below
• Credit card minimum payments
• Personal loans, buy-now-pay-later installment plans that report, 401(k) loans in some cases
• Child support and alimony you pay
• Payments on other properties you own, including the full PITIA
• Co-signed loans, even if someone else makes the payment

Usually doesn't count:

• Utilities, cell phone, internet, cable
• Insurance premiums (health, life, auto)
• Groceries, gas, daycare, tuition
• 401(k) contributions or other payroll deductions
• Medical collections and most collection accounts (they may need addressing, but they aren't a monthly payment)

That last group throws people. A family paying $2,400 a month for two kids in daycare feels stretched thin, and their DTI looks great on paper. Meanwhile someone with no daycare and a $780 truck payment looks worse to the computer. It isn't a perfect measure of how comfortable you'll feel. Which is why I tell people to run their own household budget alongside the pre-approval and buy at whatever number lets them sleep.

Student loans, cosigned debt, and the common headaches

Student loans in deferment or on an income-driven plan showing $0 aren't free. Most programs will impute a payment, commonly 0.5% of the outstanding balance per month, when the credit report shows zero. On a $60,000 balance that's $300 a month added to your ratio out of thin air. The exact treatment varies by loan program and gets updated periodically, so have your loan officer confirm the current rule against your specific numbers rather than assuming. Fannie Mae publishes its selling guide publicly if you want to read the actual language.

Cosigned auto loans for a kid or a sibling can sometimes be excluded if you can document that someone else has made the payments for the last 12 months from their own account. Cancelled checks or bank statements, not a verbal explanation.

Business debt that shows on your personal credit can sometimes come out too, if you can show the business pays it and the expense is reflected in the business returns. This comes up constantly with self-employed borrowers, and it's one of the places where a careful file makes a real difference. A lot of my work is with self-employed clients and investors, and more than a few "denials" I've reviewed were really just debts that should have been excluded.

What a DTI ceiling looks like in dollars

Rather than think in percentages, translate it. Here's the total monthly debt budget (housing plus everything else) at a 45% ratio across a few income levels.

So a household grossing $10,000 a month with a $500 car payment and $150 in card minimums has roughly $3,850 left for the full housing payment. Back out taxes, insurance, and any condo fee, and what's left is what supports the loan amount.

The income side is where files actually break

Lenders don't use your gross pay from a paystub and call it a day. Base salary is straightforward. Everything else gets averaged or scrutinized:

• Overtime, bonus, commission: generally a two-year average, and it has to be likely to continue. Declining bonus income gets used at the lower, more recent figure.
• Self-employment: net income after expenses from your tax returns, averaged, with some write-offs like depreciation added back. Write off aggressively and you shrink the income we can use.
• Part-time job: usually needs a two-year history.
• Rental income: typically 75% of gross rent, and how we document it depends on whether the property is already on your Schedule E.
• New job: an offer letter can work in some cases if it's salaried and starts before or shortly after closing.

If your income is anything other than a flat salary, get your documents in front of a lender before you shop. The number you think you make and the number that qualifies are often different by thousands a year.

Moving your DTI in 30 to 60 days

Practical levers, roughly in order of how well they work:

1. Pay off small installment loans entirely. Knocking out a $410 car payment with three payments left frees the whole $410 from your ratio. Paying it down doesn't help; only paying it off removes the payment.
2. Pay credit cards down to lower the minimum. Minimums are usually a percentage of the balance, so a big paydown lowers what counts. It helps your score too.
3. Don't add anything new. No car, no furniture financing, no store card at the register. I've watched a $0-down snowmobile purchase in New Hampshire cost someone their approval two weeks before closing.
4. Document the exclusions. Cosigned loans, business debts, and loans about to be paid off by a sale.
5. Increase the down payment. Lower loan amount, lower payment, better ratio. Gift funds from family are allowed on most programs with proper documentation.
6. Shop lower-tax or lower-fee properties. A Methuen single-family versus a Lynnfield single-family at the same price can produce different qualifying results purely from the tax bill.

One thing I'd push back on: don't close old credit cards to "clean up" your report. A zero-balance card contributes nothing to DTI and closing it can hurt your score.

Wrapping up

Run your own rough math before you talk to anyone. Add up gross monthly income, list every minimum payment from a free credit report, and see what's left when you multiply income by 0.45. That gives you a realistic starting frame, and it tells you whether the fix is more income documentation, less debt, or a different price range.

Then get an actual review of the documents, because the difference between a 46% ratio and a 43% ratio is often one excluded cosigned loan or one correctly averaged bonus. That's a paperwork problem, and paperwork problems are solvable.