Debt-to-Income (DTI) Ratio Calculator
Calculate your front-end and back-end debt-to-income ratio from gross income, housing payment and other monthly debts.
Written by Rahman · Last reviewed
Quick answer
On $6,800 of gross monthly income with a $1,900 housing payment and $600 of other debt, the front-end ratio is 27.9% and the back-end 36.8%, inside the usual 28% housing guideline but over the 36% total. Debt-to-income is your monthly debt divided by gross monthly income, and lenders read the two ratios separately: housing alone, then housing plus everything else. 43% is the upper limit for most qualified mortgages in the US.
28/36/43 are lending guidelines, not laws — some loan programs qualify borrowers above 43% with compensating factors, and some lenders set stricter limits than these.
Results are estimates for general guidance and are not financial, tax or legal advice. Except where a calculator names a currency, figures carry no currency of their own: put in pounds and you get pounds back, put in rupees and you get rupees. Figures depend on the assumptions you enter and on rates that change over time. Check current rates and speak to a qualified adviser before acting on them.
About the Debt-to-Income (DTI) Ratio Calculator
Debt-to-income ratio compares how much of your gross monthly income already goes to debt payments against how much you earn. Lenders use it, alongside credit score, to judge how much additional debt (typically a mortgage) you can safely take on.
This calculator reports both commonly used versions: the front-end ratio, covering housing costs alone, and the back-end ratio, covering housing plus every other monthly debt payment (car loans, student loans, minimum credit card payments and similar).
Front-end DTI = housing payment ÷ gross monthly income × 100 Back-end DTI = (housing payment + other debts) ÷ gross monthly income × 100
"Housing payment" should be the full payment; for a mortgage, that means principal, interest, tax, insurance and any HOA fee, not principal and interest alone.
Where the 28/36/43 numbers come from
28% and 36% are the traditional "28/36 rule" conventional-mortgage guideline: no more than 28% of gross income on housing, no more than 36% on housing plus all other debt. Neither is a law. Individual lenders set their own limits, and some loan programs qualify borrowers well outside these figures given a strong credit profile or a large down payment.
43% is the back-end ceiling the US Consumer Financial Protection Bureau uses to define a "Qualified Mortgage", a legal safe-harbor category for lenders, not a hard cap on what any borrower can be approved for. Some loan programs, including many government-backed ones, permit a higher back-end ratio than 43% with compensating factors such as a large cash reserve.
The lender's debt figure is not the one on your statements
A DTI worked out from what actually leaves your account each month can differ from the one an underwriter calculates, in both directions. The rules below are Fannie Mae's, which govern most conventional US mortgages; FHA, VA and other programs set their own.
- Student loans in deferment or forbearance still count. With no payment due, the lender may use 1% of the outstanding balance or a fully amortizing payment, so $40,000 of deferred loans enters the ratio as $400 a month.
- Applied to the example above, that $400 lifts the back-end ratio from 36.8% to 42.6% on debt the borrower is not currently paying anything toward.
- A borrower on an income-driven plan whose documented payment is $0 can be qualified at $0, which is a different case from deferment.
- In the other direction, an instalment loan with ten or fewer payments left can generally be left out, unless it significantly affects the borrower's ability to pay. Dropping a $350 car payment in its final months takes the same example from 36.8% to 31.6%.
Enter the figures a lender would use rather than the ones you currently pay if the purpose is to predict an approval: add an imputed payment for any deferred loan, and consider running the numbers both with and without a debt that is nearly paid off.
Frequently Asked Questions
What counts as a monthly debt for DTI?
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Recurring, required payments: mortgage or rent, car loans, student loans, minimum credit card payments, personal loans and similar. Utilities, groceries, insurance premiums and other living costs are not included.
Is a lower DTI always better?
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For loan approval, yes: a lower DTI signals more room in your budget to absorb a new payment. It says nothing about whether the specific loan or spending decision is otherwise a good one.
Does DTI use gross or net income?
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Gross: income before tax and other deductions. This is standard lending practice, though it means your actual take-home budget is tighter than the DTI percentage alone suggests.
How is DTI different from a credit utilization ratio?
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DTI compares monthly debt payments to monthly income. Credit utilization compares your credit card balances to your credit limits, a separate figure that affects your credit score rather than loan affordability directly.
Sources
- CFPB — What is a debt-to-income ratio? — US regulator explaining the 43% qualified-mortgage back-end DTI limit.
- Fannie Mae Selling Guide B3-6-05 — Monthly Debt Obligations — The underwriting rules behind the section on how a lender counts debt: for student loans that are deferred or in forbearance the lender "may calculate a payment equal to 1% of the outstanding student loan balance" or a fully amortizing payment; a documented $0 income-driven payment may be used as $0; and instalment debt counts when more than ten monthly payments remain. Fannie Mae conventional loans only.