Mortgage Calculator
Monthly payment & interest.
Mortgage Calculator at a glance
Mortgage Calculator is a free online calculator you can use right now to monthly payment & interest โ no account, no install and no usage limit. It runs entirely inside your browser, so whatever you enter stays on your own device.
- Price
- Free โ no trial, no paid tier, no watermark
- Sign-up
- Not required
- Where it runs
- In your browser โ nothing is uploaded to a server
- Works on
- Chrome, Safari, Firefox and Edge โ desktop, tablet and phone
- Category
- Calculators
About Mortgage Calculator
Enter the loan amount, interest rate and term to get the monthly payment, the total interest paid and the overall cost.
The total interest figure is the one worth looking at, because it is routinely much larger than people expect. A 25-year mortgage at a moderate rate commonly costs more in interest than half the amount borrowed, and at higher rates the interest can approach or exceed the principal. Monthly affordability is what lenders discuss; total cost is what you actually pay.
Understanding amortisation explains why overpaying early matters so much. Each payment covers the interest accrued that month plus whatever is left over, which reduces the principal. Early on, when the balance is largest, most of the payment is interest โ in the first years of a long mortgage the balance barely moves. Because every future interest charge is calculated on the outstanding balance, an overpayment early removes interest from every remaining month, while the same amount paid in the final years saves almost nothing.
This calculation covers principal and interest only. The actual monthly cost of owning a home also includes buildings insurance, property tax or council tax, any service charge or ground rent, and mortgage insurance where the deposit is small. Budgeting from the principal-and-interest figure alone reliably understates what you will pay, often substantially.
How to use Mortgage Calculator
- Enter the amount borrowed, the annual interest rate and the term in years.
- Read the monthly payment, total interest and total repaid.
- Adjust the term or rate to compare scenarios before speaking to a lender.
Frequently asked questions
Why is the total interest so high?
Because interest is charged on the outstanding balance every month over a long term. On a 25-year mortgage the interest commonly exceeds half the amount borrowed, and at higher rates it can approach the principal itself.
Does overpaying early really save more?
Yes, substantially. An overpayment reduces the balance that all future interest is calculated on, so paying early removes interest from every remaining month. The same amount paid near the end saves very little.
Does this include tax, insurance and fees?
No โ it covers principal and interest only. Your real monthly cost also includes insurance, property or council tax, any service charge, and mortgage insurance if your deposit was small. Budget for those separately.
Should I choose a shorter or longer term?
A shorter term means higher monthly payments and dramatically less total interest. A longer term is more affordable monthly and much more expensive overall. Compare both here, and consider whether overpayments on a longer term give you flexibility with a similar outcome.