Mortgage Pre Approval Calculator - Estimate What a Lender Might Allow

How to use

1. Enter Annual household income - before tax, for everyone who would be on the loan.
2. Add Monthly debts: car, student and card minimums as they appear on your credit report, not your full balances.
3. Enter your Down payment, the Rate you expect, and pick a Term (30, 20 or 15 years).
4. Set Property tax rate (annual %), Insurance (annual $), HOA (monthly $), and choose a DTI limit - 36% conservative or 43% conventional max.
5. Press Compute pre-approval estimate to see the max loan, estimated price, monthly PITI and the DTI used - plus a PMI estimate line if your down payment is below 20%.
6. Treat the result as a planning range: re-run it at different rates and DTI limits, then confirm with an actual lender's pre-approval letter before house hunting.

General information only — not medical, financial or legal advice. Figures cross-checked against public official sources (IRS / HMRC / NHS / WHO guidance); content last reviewed September 2026. For decisions that matter, confirm with a licensed professional in your country.

About this tool

Lenders size a mortgage with one core ratio: the debt-to-income limit, commonly 36% conservatively and 43% as the conventional maximum. This calculator applies that rule the way an underwriter starts: your Annual household income sets the ceiling, your Monthly debts are subtracted first, and what remains is the largest monthly PITI (principal, interest, property tax, insurance, HOA) you could carry. It then solves for the highest loan and price that fit, using your Down payment, the Rate you expect, the Term, and your tax and insurance settings. The result is an estimate of what a lender MIGHT approve - never an offer, and not financial advice.

Underwriting starts from gross monthly income, then applies caps: many conventional programs treat 36% of gross income as the comfortable total-debt ceiling and up to 43% (sometimes more with strong compensating factors such as high credit scores or large cash reserves) as the outer limit. Within the resulting budget, the lender subtracts the full housing payment - principal and interest, property taxes, insurance, HOA dues and, below 20% down, PMI. Debts from your credit report (car loans, student loans, card minimums) come out of the same budget. Lenders also add their own overlays beyond these rules, and final numbers shift with the appraisal, the rate lock and the loan program.

The rate moves the answer more than any other field. At 6.5% over 30 years, each $100,000 borrowed costs about $632 per month in principal and interest; at 5.5% about $568, and at 7.5% about $699. A one-point difference is roughly $60-70 per $100,000 - enough to move a maximum price by tens of thousands. That is why rate shopping matters: multiple mortgage inquiries within a focused window (commonly about 45 days) usually count as a single inquiry for scoring purposes. Re-run this calculator at two or three rates, then compare real Loan Estimates line by line.

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