Mortgage Calculator — Monthly Payment
Model monthly principal-and-interest payments on a fixed-rate amortizing mortgage and compare extra principal payments. The result is not total housing cost or a lender’s approval decision.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
Numbers stay on your device. Nothing is sent to a server.
Optional. Applied to principal each month after the scheduled payment.
How to use this tool
Enter balance, annual rate, years and an extra monthly amount. The prominent payment figure is the scheduled base payment, with the extra shown separately, so combine them when planning monthly cash flow.
Results and examples
At zero interest, 12,000 repaid over one year has a base payment of 1000 per month. Extra principal can shorten repayment; the visible table shows the first twelve periods rather than the complete term.
Limitations
- Property tax, homeowners insurance, association charges and mortgage insurance are excluded.
- Variable rates, prepayment fees and conditions beyond the 600-month horizon need separate analysis.
Fields
| Field | Guidance and constraints |
|---|---|
| Loan amount | Accepted range: 1–100000000 · Input step: 100 |
| Annual interest rate | Accepted range: 0–50 · Input step: 0.01 |
| Term (years) | Accepted range: 1–50 · Input step: 1 |
| Extra monthly payment | Optional. Applied to principal each month after the scheduled payment. · Accepted range: 0–100000 · Input step: 10 |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Sources
Frequently asked questions
What is the zero-interest monthly payment?
At zero interest, 12,000 repaid over one year has a base payment of 1000 per month. Extra principal can shorten repayment; the visible table shows the first twelve periods rather than the complete term.
Does the headline payment include the extra?
Property tax, homeowners insurance, association charges and mortgage insurance are excluded. Variable rates, prepayment fees and conditions beyond the 600-month horizon need separate analysis.
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