28/36 Rule Calculator

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Front-end ratio - 28% rule

Back-end ratio - 36% rule

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28/36 rule status Enter income, housing costs, and debts to check the 28/36 rule.
Financial Calculator

28/36 Rule Calculator

Use this 28/36 rule with income, do you want to input individual housing expenses separately?, and principal loan amount to estimate costs, returns...

It is a screening rule, not an approval guarantee. Lenders may use different limits depending on credit profile, loan program, reserves, property taxes, insurance, and local underwriting standards.

What is the 28/36 rule of debt ratio?

The 28/36 rule compares monthly housing costs and total monthly debt with gross monthly income. The front-end ratio checks housing affordability, while the back-end ratio checks the broader debt burden.

It is a screening rule, not an approval guarantee. Lenders may use different limits depending on credit profile, loan program, reserves, property taxes, insurance, and local underwriting standards.

28/36 rule formula

Front-end ratio = housing costs / income x 100. Back-end ratio = total debt / income x 100.

Housing costs may be entered directly or built from individual housing expenses. When itemized expenses are enabled, the calculator adds principal loan amount, loan interest, property tax, and insurance before calculating the front-end ratio.

  • Housing costs are compared with income for the 28% rule.
  • Housing costs plus other debts are compared with income for the 36% rule.
  • Use monthly amounts for income, housing costs, and debt payments.

How to calculate 28/36 mortgage rule - an example

If monthly income is $5,000 and housing costs are $1,400, the front-end ratio is 28%. If other monthly debts are $400, total debt is $1,800 and the back-end ratio is 36%.

A result at or below both benchmarks suggests the scenario fits the conventional 28/36 guideline. A higher result does not automatically make the mortgage impossible, but it should trigger a closer review of affordability and lender rules.

What price house can I afford?

The calculator does not convert a debt ratio into a home price by itself because the affordable price depends on down payment, rate, term, property tax, insurance, HOA fees, and lender rules.

Use the housing-cost estimate as a monthly affordability checkpoint, then test the same assumptions in a mortgage calculator to translate the payment into a possible purchase price.

Frequently asked questions

Common questions about 28/36 rule, assumptions, costs, rates, and how to read the result before making a money decision.

What numbers should I include in 28/36 rule?

Include the amounts, rates, dates, fees, and recurring costs that belong to the same financial decision. Excluding one major cost can make the result look better than the real outcome.

How do rates affect 28/36 rule?

Rates can change borrowing cost, investment growth, tax, discount, or return. Check whether the rate is annual, monthly, fixed, variable, simple, or compounded before using it.

Why does the time period matter for 28/36 rule?

The time period affects compounding, repayment, inflation, fees, and cash flow. A monthly assumption should not be mixed with an annual one unless it has been converted correctly.

Can I use 28/36 rule for budgeting?

Yes, as a planning estimate. For a real budget, include cash flow timing, taxes, fees, insurance, maintenance, and any expenses that the calculator does not ask for directly.

Why might my 28/36 rule estimate be wrong?

Common causes are outdated rates, missing fees, tax assumptions, rounded numbers, optimistic growth, or mixing values from different periods or offers.

What should I review before acting on 28/36 rule?

Review the source numbers, compare them with official statements or quotes, and test a conservative scenario so the decision still makes sense if conditions change.