Last reviewed August 28, 2026

Mortgage Calculator: Formula, Scenarios & Interpretation

Estimate principal and interest plus taxes, insurance, HOA and mortgage insurance with a monthly housing-cost breakdown.

What the calculation measures

The principal-and-interest payment amortizes the financed amount over the selected term at the stated annual rate. Taxes, insurance, HOA and mortgage insurance are added as separate monthly estimates.

How to interpret the result

Use the all-in monthly housing estimate for budgeting, but keep principal-and-interest separate when comparing loan terms.

Run scenarios instead of one answer

Change the most uncertain input and compare outcomes. A calculator is most useful when it shows sensitivity, not when one estimate is treated as a guarantee.

Limits and assumptions

This is not a loan quote. Escrow, closing costs, variable rates, points and lender-specific fees can change actual payments.

Try the browser tool

Work with your file locally.

Open Mortgage Calculator