28/36 Rule Calculator

Enter your gross monthly income, housing costs, and other debt payments to see whether you meet the 28% housing and 36% total-debt limits lenders use.

Quick Facts

The rule
Housing ≤ 28% and total debt ≤ 36% of gross monthly income
Front-end ratio = housing ÷ income; back-end ratio = (housing + all debt payments) ÷ income.

Your Results

Calculated
Front-end ratio
-
Housing ÷ gross income (limit 28%)
Back-end ratio
-
All debt ÷ gross income (limit 36%)
Max housing budget
-
28% of your gross monthly income
Max total debt payments
-
36% of your gross monthly income

Ready

Enter your income, housing costs, and other debts, then press Calculate.

What this calculator does

The 28/36 rule is a classic housing-affordability guideline used by mortgage lenders. It says your monthly housing costs should not exceed 28% of your gross (pre-tax) monthly income, and your total monthly debt payments — housing plus everything else — should not exceed 36%. This calculator computes both ratios from your figures and shows the maximum housing payment and total debt load that would keep you inside the rule.

The formulas

  • Front-end ratio = monthly housing costs ÷ gross monthly income × 100. Housing costs mean PITI — principal, interest, property taxes, homeowners insurance — plus HOA dues. The guideline limit is 28%.
  • Back-end ratio = (housing costs + other monthly debt payments) ÷ gross monthly income × 100. Other debts include car loans, student loans, personal loans, and minimum credit card payments. The guideline limit is 36%.
  • Maximum budgets: max housing = 0.28 × gross monthly income; max total debt = 0.36 × gross monthly income.

Getting accurate results

  • Use gross monthly income (before taxes and deductions), not take-home pay — the rule is defined on gross income.
  • Include the full housing payment: taxes, insurance, and HOA dues, not just principal and interest.
  • For credit cards, count the minimum required monthly payment, not the full balance; utilities and groceries are not debts for this test.

Interpreting the output

If both ratios are at or below their limits, your housing costs fit the conservative benchmark most lenders start from. If the front-end ratio exceeds 28% or the back-end ratio exceeds 36%, that does not automatically mean a loan denial — many programs allow higher debt-to-income ratios — but it does mean less slack in your monthly budget. The gap between your current housing payment and the 28% maximum shows how much room you have before hitting the guideline.

Next steps

  • Compare the 28% maximum housing budget against real listings or rent quotes in your market
  • If the back-end ratio is the binding limit, model paying down a car loan or card balance and re-run
  • For an actual mortgage decision, confirm ratios with your lender — underwriting rules vary by program and credit profile

Frequently Asked Questions

What is the 28/36 rule?
It is a lending guideline for housing affordability. Monthly housing costs (mortgage principal and interest, property taxes, homeowners insurance, and HOA dues) should not exceed 28% of gross monthly income, and total monthly debt payments — housing plus car loans, student loans, and minimum credit card payments — should not exceed 36%.
What counts as housing costs in the 28% front-end ratio?
Housing costs typically mean PITI: mortgage principal, interest, property taxes, and homeowners insurance, plus HOA or condo dues if you pay them. Renters can apply the same test using monthly rent plus renters insurance. Utilities, maintenance, and groceries are not included.
What debts count toward the 36% back-end ratio?
The back-end ratio adds recurring debt obligations to your housing costs: car payments, student loans, personal loans, and minimum required credit card payments. It does not include everyday living expenses such as utilities, phone bills, or groceries.
Is the 28/36 rule a strict requirement for getting a mortgage?
No. It is a conservative guideline, not a law. Many lenders approve loans with higher debt-to-income ratios — some programs allow back-end ratios well above 36% — while borrowers with strong credit or large down payments get extra flexibility. Staying within 28/36 simply leaves a wider margin of safety in your budget.

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