Debt-to-Income Ratio (DTI)

Add up the monthly payments you are obligated to make on debts, divide by your gross monthly income, the amount you earn before taxes and other deductions are taken out, and multiply by 100. Use the required payment, not the balance and not what you choose to pay: for a credit card, that is the minimum payment on the statement. If your pay varies, lenders look for income that is stable enough to count on.

Everyday living costs such as utilities, groceries, phone plans and health insurance premiums are not debts and stay out of the ratio, even though they compete for the same paycheck. For a Mortgage application, Fannie Mae’s Selling Guide lists the monthly obligations that go into its total ratio:

Mortgage lenders often look at two versions of the ratio. The front-end ratio, sometimes called the housing ratio, counts only the housing payment: principal, interest, taxes, insurance and dues divided by gross monthly income. The back-end ratio counts every debt payment, housing included, and is what most people mean by DTI.

A long-standing lender rule of thumb puts the front-end ratio at about 28% and the back-end ratio at about 36%. Those figures are guidelines, not regulations, and the programs lenders actually underwrite to set their own limits (see the table). The VA, for example, adds the new housing payment to long-term obligations and treats 41% as its standard, while Fannie Mae works from the total ratio.

The front-end ratio tells you whether the house itself is affordable; the back-end ratio tells you whether the house plus everything else is. Someone with no other debt can carry a larger housing payment within the same back-end limit than someone with a car loan and student loans, which is why paying off a car loan before house hunting can raise the housing payment you qualify for.

There is no single legal maximum DTI. Under the federal ability-to-repay rule, a mortgage lender must consider your monthly debt-to-income ratio or your residual income before making a loan. The rule’s General Qualified Mortgage definition once capped DTI at 43%, and that number still circulates, but a CFPB final rule issued in December 2020 removed the cap and replaced it with a price test, with compliance required from October 1, 2022. A typical first-lien loan generally stays a General QM only if its APR is less than 2.25 percentage points above the average prime offer rate, and smaller loans and subordinate liens get higher thresholds. Lenders must still consider DTI or residual income and verify the income and debts behind it.

In practice, limits come from the programs that buy, guarantee or insure loans. Fannie Mae caps DTI at 50% for loans run through Desktop Underwriter, its automated underwriting system. For manually underwritten loans its maximum is 36%, which can stretch to 45% when the borrower meets its credit score and reserve requirements. The VA’s standard is 41%, and a VA loan can go higher without a second-level review when residual income beats the VA guideline by at least 20%. Individual lenders can set tighter limits than any of these.

Outside mortgages, auto lenders, card issuers and personal-loan lenders set their own thresholds, and the CFPB notes that DTI limits differ by loan product and lender.

Because DTI is a ratio, you can lower it by shrinking payments or by raising gross income, and payment changes usually move faster. The strongest single lever is eliminating a whole payment. Paying off a car loan with a few thousand dollars left removes its entire monthly payment from the ratio, while the same money put toward a large installment loan shortens its term but leaves its required payment unchanged.

That is the one place where the debt snowball, which clears the smallest balance first, has a measurable edge over the debt avalanche. The avalanche minimizes interest, but it can leave every required payment in place for months while it works on one large, expensive balance. If a mortgage application is a year away, check which order lowers your ratio in time. Other levers:

The most common error is mixing up gross income and take-home pay. Lenders use gross income, so a ratio a lender accepts can feel much heavier in your budget. At a 43% DTI on $7,500 of gross monthly income, debt payments come to $3,225; if take-home pay is $5,700, those payments consume about 57% of what actually reaches your account.

Other frequent mistakes are counting balances instead of payments, forgetting co-signed loans or deferred student loans that a lender may still count, and treating the maximum a lender allows as a comfortable budget. A lender’s limit answers whether you can probably make the payments. Your own plan should also ask what else those dollars need to do, from building an emergency fund to saving for retirement. A budget built on take-home pay, such as the 50/30/20 rule, is a better test of comfort than any lender ceiling.