This works backward from your income to a sustainable home loan amount, using the widely cited 28/36 mortgage-underwriting guideline.
How it works
The 28/36 rule
Housing costs ≤ 28% of gross monthly income · total debt ≤ 36% of gross monthly income
Whichever ratio binds first — the housing-specific 28% limit, or the 36% total-debt limit after other debt is subtracted — sets the real ceiling.
A guideline, not a guarantee
28/36 is a widely used rule of thumb, not a law. Actual lender qualification depends on credit score, down payment, debt type and the specific lender’s own overlays, which can be more permissive or stricter than 28/36 in either direction. This calculator reports what the guideline itself implies; it doesn’t predict what any specific lender will approve.
How to use this calculator
- Enter your gross monthly income.
- Enter any other monthly debt payments.
- Enter an expected rate and term to convert the payment limit into a loan amount.
Frequently asked questions
Why gross income and not take-home pay?
Because that’s the convention lenders actually use for this ratio — calculating against take-home pay would produce a smaller, misleadingly conservative number compared to what lenders are actually measuring.
What counts as “other debt”?
Car loans, student loans, minimum credit card payments and any other recurring debt obligation — not everyday living expenses like groceries or utilities, which aren’t part of this ratio.
Why did my other debt reduce my home budget by more than its own amount?
It doesn’t reduce it by more than its own amount — it’s simply that the back-end (36%) limit, minus your other debt, can come out lower than the front-end (28%) limit, and whichever is lower is the one that binds.
Can I actually get approved for exactly this amount?
Maybe, maybe not — this shows what the guideline implies, not a lender’s actual decision, which depends on many factors beyond income and existing debt.
What if my other debt alone already exceeds 36% of my income?
Then this calculator shows zero room for housing under the guideline — a real signal that other debt would need to come down before a lender following this rule would likely approve a mortgage.
