A $400,000 house at 7% over 30 years costs about $2,661 a month — and roughly $558,000 in interest over the life of the loan. The monthly payment, not the listing price, is what determines what you can actually afford, and small rate differences compound into tens of thousands of dollars.
This calculator shows the full picture: monthly payment, total interest, and total cost from loan amount, rate, and term. Then try an extra monthly payment — even $200 — and watch years fall off the loan and interest melt away. Everything is computed locally in your browser; no financial details are sent anywhere.
Run the numbers in 3 steps
- Open the faymox Mortgage Calculator.
- Enter the loan amount, interest rate, and term in years.
- See your monthly payment and total interest — then add an extra monthly payment to see the years and interest you would save.
FAQ
Does it include property tax and insurance?
No — it calculates principal and interest, which is the core of the loan. Add your local tax and insurance estimates on top for the full monthly cost.
How do extra payments save money?
Extra payments go straight to principal, which shrinks the balance that interest accrues on. Even a small extra amount each month can cut years off a 30-year loan.
Is my financial data sent anywhere?
No. Every calculation runs locally in your browser — the numbers you type never leave your device.