Mortgage Calculator

Mortgage Calculator works out the monthly payment on a repayment mortgage, and then shows you the part most calculators leave out: what the loan costs in total, and how slowly the balance actually falls in the early years.

The payment comes from the standard annuity formula. Each month, interest is charged on the balance that is left, and whatever remains of your payment reduces the debt. Early on, almost all of the payment is interest and the balance barely moves. That reverses towards the end. Seeing the yearly balance makes this concrete in a way a single monthly figure never does.

Two numbers are worth paying attention to. The first is total interest, which on a long mortgage can approach or exceed the amount borrowed. The second is what happens when you shorten the term: a mortgage over 20 years rather than 25 costs more each month but far less in total, and the calculator shows both so you can judge the trade.

The result is the capital and interest payment only. A real mortgage statement also carries buildings insurance, any mortgage protection, and in some countries property tax collected by the lender. Those vary too much to guess at, so they are left out rather than invented.

This is arithmetic, not financial advice. It tells you what the numbers do; it cannot tell you whether a decision is right for your circumstances. For anything that matters, check the figures against the actual offer and talk to someone qualified.

Everything is worked out inside your browser. Nothing you enter is uploaded, logged or stored, which matters for the financial calculators in particular: the figures you put into them are nobody else's business.

• Monthly payment from the standard annuity formula
• Total repaid and total interest over the full term
• Loan-to-value shown from the price and deposit
• Year-by-year table of interest, capital and remaining balance
• Compare two terms side by side to see what shortening costs and saves
• Works in any currency, because it is arithmetic rather than a product
• Nothing is uploaded; the figures stay on your device

The mortgage calculator is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:

• Checking a lender's quoted payment before you sign anything
• Seeing whether a shorter term is affordable month to month
• Working out how much deposit changes the payment
• Understanding why the balance has barely moved after three years
• Comparing two offers at different rates and terms