Mortgage Calculator Calculators
Work out monthly repayments, total interest and the true cost of a mortgage.
Mortgage Calculator is a free online tool that work out monthly repayments, total interest and the true cost of a mortgage. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Calculators
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- 5
- Works offline
- Yes, after the first visit
About Mortgage Calculator
This is a standard amortising repayment calculation: the monthly payment stays level, and the split between interest and principal shifts over the term. It covers principal and interest only — property taxes, insurance and service charges sit on top.
How to use it
- Enter property price, deposit / down payment and interest rate.
- Adjust the remaining 2 settings if the defaults do not fit your case.
The 5 settings
| Setting | What it does | Default |
|---|---|---|
| Property price | A numeric value. | 350000 |
| Deposit / down payment | A numeric value. | 70000 |
| Interest rate | A numeric value. | 5.25% |
| Term (years) | Range 1–50. | 25 |
| Currency | Choose from 7: USD $, GBP £, EUR €, INR ₹, AUD A$, CAD C$…. | USD $ |
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
| Controls | Property price, Deposit / down payment, Interest rate, Term (years), Currency |
Questions
What is not included in this payment?
Property taxes, buildings insurance, service charges, ground rent and any mortgage insurance. Depending on where you live, those can add 20–40% on top of the figure shown.
Why is total interest so much higher on a longer term?
Because you hold the debt for longer. Extending 25 years to 35 lowers the monthly payment by perhaps 15% while adding far more than that in total interest — the calculator shows both so the trade is visible.
Does this handle a fixed period followed by a variable rate?
No — it assumes one rate for the whole term. Run it twice with different rates to see the range you might be exposed to when a fixed period ends.