MortgageAffordabilityTools

Debt-to-Income Calculator

Calculate front-end and back-end debt-to-income ratios and see what is left after every debt payment.

Last reviewed

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Free · No sign-up · Runs in your browser

Debt-to-income is the single most influential number in a mortgage application, and it comes in two versions that measure different things. The front-end ratio counts housing costs only; the back-end ratio counts every recurring debt payment a lender can see.

This calculator reports both from your own figures, along with what is left each month once every debt is serviced - which is the number that determines whether the arrangement is actually comfortable.

Your numbers

Results update as you type. Nothing is sent anywhere.

Result

Front-end ratio

25%

Back-end ratio

35%

Total monthly debt
$2,800
Income after debt payments
$5,200

Front-end ratio counts housing costs only. Back-end ratio counts every recurring debt payment a lender sees on your credit report.

Lender thresholds differ by program and by file. Treat these numbers as a self-check, not as an approval decision.

How to use the debt-to-income calculator

  1. Enter gross monthly income before tax.
  2. Enter the total monthly housing payment including tax and insurance.
  3. Enter every other recurring debt payment: cars, cards, student loans, personal loans.
  4. Read both ratios and the income remaining.

What people use this for

  • Checking where you stand before applying for a mortgage.
  • Seeing which debt to clear first to improve the ratio.
  • Understanding why an application was declined on ratio grounds.
  • Tracking the ratio as debts are paid down.

Worked examples

Every figure below is produced by running this calculator against the example inputs, so the numbers always match the tool.

A comfortable position

$8,000 gross monthly income, $2,000 housing payment, $800 of other debts.

Front-end ratio
25%
Back-end ratio
35%
Income after debt payments
$5,200

A stretched position

The same income with a $2,800 housing payment and $1,400 of other debts.

Front-end ratio
35%
Back-end ratio
52.5%
Income after debt payments
$3,800

What lenders count and what they do not

The back-end ratio includes payments that appear on a credit report: mortgage or rent, car loans, credit card minimums, student loans, personal loans and court-ordered payments. It generally excludes utilities, insurance premiums, groceries and other living costs.

That is why a ratio can look comfortable while a budget does not. The ratio measures debt service against income, not the cost of living, and the difference between the two is where households get into difficulty.

Improving the ratio

Two levers: raise income or reduce monthly debt payments. Reducing payments works fastest, and the debt to target is the one with the largest payment relative to its balance - frequently a car loan rather than the largest total debt.

Paying a card down enough to reduce the minimum, or clearing a small loan entirely, can move the ratio more than paying a much larger amount off a mortgage. Lenders look at the payment, not the balance.

Methodology and assumptions

What this calculator does, and what it deliberately does not do.

  • Front-end ratio = housing payment ÷ gross monthly income. Back-end ratio adds all other monthly debt payments.
  • Gross income before tax is used, which is the lender convention.
  • Thresholds differ by loan programme and lender; no benchmark is applied here.
  • Results are estimates. Real quotes depend on credit, income, property, loan programme and lender pricing at the time of application.
  • Nothing you type is transmitted or stored - the calculation runs entirely inside your browser.

This calculator is provided for informational and educational purposes only. Results are estimates and may not reflect actual rates, fees, taxes, or market conditions.

This website is not a lender, a mortgage broker or a financial adviser. It does not originate loans, does not accept applications and does not forward your details to anyone.

Actual loan terms depend on credit history, income, the property, the loan programme and lender pricing at the time of application. Only a lender can tell you what you qualify for.

Frequently asked questions

What is an acceptable DTI?

It varies by programme and by the strength of the rest of the file. Compensating factors such as reserves or a large deposit frequently allow higher ratios.

Do I include the rent I pay now?

For a purchase, use the proposed housing payment rather than current rent - that is what the lender assesses.

Are student loans in deferment counted?

Usually yes, at a calculated payment even when nothing is currently due. How that payment is calculated differs by programme.

Does a low DTI guarantee approval?

No. Credit history, employment stability, reserves and the property all matter. The ratio is one gate among several.

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