Mortgage Calculator
Monthly payment, total interest and full amortization for any home loan scenario.
Free · No sign-up · Runs locally in your browser · Also available in Chinese (中文)
What is Mortgage Calculator?
A mortgage calculator converts a loan's principal, interest rate and term into the one number that matters month to month: the payment. It uses the standard amortization formula, so the figure matches what banks quote for a fixed-rate loan.
Beyond the monthly payment, it shows total interest paid over the life of the loan and how each payment splits between interest and principal over time. Seeing that split is often the moment buyers realize why extra principal payments early in a loan save so much interest.
How to use it
- 1Enter the loan amount (or home price minus down payment).
- 2Set the annual interest rate offered by your lender.
- 3Choose the term in years — 15, 20 or 30 are typical.
- 4Read the monthly payment, then explore total interest and the amortization breakdown.
Common use cases
- Comparing a 15-year versus a 30-year loan before committing to a term.
- Testing how an extra payment per year shortens the payoff date.
- Checking affordability by keeping housing cost below a target share of income.
Frequently asked questions
▸Does the payment include taxes and insurance?
The core result is principal and interest only. Add property tax and insurance estimates yourself if you want the full housing payment — the tool keeps them separate so the loan math stays transparent.
▸Why does early interest look so large?
Interest accrues on the outstanding balance, which is largest at the start. As principal shrinks, the interest share of each payment falls — that is the amortization curve you can inspect.