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Debt-to-Income Ratio Calculator

Debt-to-income ratio is the single number that decides most mortgage applications. It comes in two forms — housing costs against income, and all debt against income — and lenders start from a guideline of 28% and 36%. This calculator computes both, tells you which one is binding, and quantifies exactly how much debt you would need to clear to reach the guideline.

How to use this calculator

  • - Use gross monthly income, before tax and deductions.
  • - Housing means the full payment: principal, interest, tax, insurance, mortgage insurance and HOA.
  • - Count only debts that appear on a credit report — not utilities, groceries or childcare.

Your monthly numbers

Gross income, before tax.

Income

Before tax and deductions, all borrowers combined.

Obligations

Principal, interest, property tax, insurance, mortgage insurance and HOA.

Minimum payments on cards, car and student loans, child support. Not utilities or groceries.

Back-end ratio

35.9%

Front-end 28.2% · above the guideline, within agency limits

Housing ratio (front end)Guideline 28%28.2%
Total debt ratio (back end)Guideline 36%, agency max 45%35.9%
Total obligations$3,050
Left after obligationsEverything else your household lives on$5,450

Above the guideline, within agency limits

Past 36% but inside what agency-backed conventional loans commonly allow. Approval is normal; expect the file to be looked at more closely.

What this assumes

  • Ratios are measured against gross monthly income of $8500, before tax.
  • The classic guideline is 28% housing and 36% total debt (Consumer Financial Protection Bureau).
  • Above the 36% guideline but within the 45% that agency-backed conventional loans commonly allow.

The two ratios

The 28/36 figures are a starting point, not a wall. Agency-backed conventional loans routinely accept a back-end ratio up to 45%, and up to 50% where there are compensating factors — significant cash reserves, a high credit score, a large down payment, or a long unbroken employment history. FHA can go higher still with manual underwriting.

  • Front-end, or housing ratio — guideline 28%: Your total monthly housing payment divided by gross monthly income. Housing means the whole payment: principal, interest, property tax, homeowners insurance, mortgage insurance and HOA dues. Not just principal and interest.
  • Back-end, or total debt ratio — guideline 36%: Housing plus every other monthly obligation on your credit report, divided by the same gross income. This is the one that usually binds, and the one that responds to paying down a car loan.

What counts, and what does not

  • Counted: Minimum credit card payments, car loans and leases, student loans (a percentage of the balance where the loan is in deferment), personal loans, court-ordered child support and alimony, and any other mortgage you hold.
  • Not counted: Utilities, mobile phone, groceries, insurance premiums that are not financed, childcare, medical bills not in collections, and anything you pay by choice rather than by contract. This surprises people: childcare can dwarf a car payment and has no effect on the ratio.
  • Income that counts: Gross pay before tax, and only income you can document as stable and likely to continue. Salary and hourly wages count immediately; bonus, commission and self-employment income normally require a two-year history and are averaged over it. Income you started receiving three months ago will usually not be counted at all.

Improving your ratio before you apply

Paying off a small loan entirely beats paying down a large one. The ratio is driven by monthly payments, not balances, so eliminating a $400 car payment with 8 months remaining does far more than putting the same money against a mortgage-sized student loan. Some lenders will exclude a debt with fewer than ten payments left, which makes clearing a nearly-finished loan doubly effective.

Do not close credit cards to improve DTI — an unused card contributes nothing to the ratio, and closing it reduces available credit in a way that can lower your score. Do avoid taking on new debt in the months before applying, and be aware that financing a car after pre-approval but before closing is one of the most common ways an approved loan falls apart.

Frequently asked questions

What is a good debt-to-income ratio for a mortgage?

A back-end ratio at or under 36% is comfortably inside the classic guideline and is where the best pricing lives. Up to 45% is routinely approved on agency-backed conventional loans. Between 45% and 50% approval depends on compensating factors. Above that, the agencies will not normally buy the loan.

Does rent count in debt-to-income ratio?

Not for a purchase. Your current rent disappears when you buy, so it is replaced in the calculation by the proposed housing payment rather than added to it. Rent on a property you will keep — a second home you are not selling — does count.

Do student loans in deferment count toward DTI?

Yes, in almost every programme. Deferred or income-driven student loans are counted using either the documented payment or a percentage of the outstanding balance, depending on the loan programme and the specific documentation available. A $0 income-driven payment does not mean the loan counts as zero.

Can I get a mortgage with a 50% DTI?

It is possible but not routine. 50% is the outer edge of what agency-backed conventional loans reach, and getting there requires compensating factors — substantial reserves, an excellent credit score, or a large down payment. FHA with manual underwriting sometimes goes further. Expect a slower process and more documentation.

Reference sources

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For developers

This calculation is also available as a REST API and through an MCP server, both running the same engine as this page — so the figures match by construction rather than by convention. No key required.