Mortgage Payment Calculator
Quick answer
A mortgage payment is fixed by three numbers: the amount you borrow, the annual interest rate and the term. Enter them below to see the monthly payment and what the loan costs in total.
Estimate your monthly payment
Principal and interest only — property tax, insurance and lender fees are not included.
What you borrow, after the deposit.
The nominal yearly rate your lender quotes.
Monthly payment
$1,896
360 payments
Total interest
$382,632
56% of everything you pay
Total paid
$682,632
$300,000 borrowed
At 6.5% over 30 years you repay $682,632 on $300,000 borrowed. Change the term to see how much of that is the term rather than the rate.
A repayment mortgage is an annuity loan: every month you pay the same amount, but the split between interest and principal changes. Early on most of the payment is interest; by the end almost all of it reduces the balance. That is why a small change in the rate moves the total cost so much more than it moves the monthly figure.
This calculator uses the standard annuity formula with no lender fees, insurance or property tax added, so the number you see is pure principal and interest. Add local costs separately when you compare offers.
How the monthly payment is calculated
The payment comes from the annuity formula: the loan amount multiplied by the monthly rate, divided by one minus the monthly rate compounded backwards over the number of payments. The monthly rate is simply the annual rate divided by twelve.
Because the rate compounds, doubling the term does not halve the payment. Going from a 15-year to a 30-year term on the same loan typically cuts the monthly payment by around a third, while more than doubling the interest you pay over the life of the loan.
What this calculator does not include
Property tax, building insurance, mortgage insurance and any lender arrangement fee are excluded. In the United States these are often bundled into the monthly payment as escrow, which is why a lender quote can be noticeably higher than a principal-and-interest figure.
Rate type also matters. A fixed rate keeps this payment stable for the whole term; a variable or tracker rate does not, so treat the result as the payment at today's rate rather than a guarantee.
Why overpaying early has an outsized effect
Interest is charged on the outstanding balance, so money paid in the first years removes interest that would otherwise have been charged every month for decades. The same overpayment made in the final years saves very little.
Compare the total interest figure below at two different terms before you decide. The gap is usually the single largest number in the whole transaction and it rarely appears in the headline rate advertised by a lender.
Frequently asked questions
- Does a shorter term always cost less?
- In total interest, yes — a shorter term means fewer months of interest on a balance that falls faster. The monthly payment is higher, so the real question is how much monthly payment you can carry without straining everything else.
- Why is my lender's quote higher than this figure?
- This calculator shows principal and interest only. Lender quotes usually add property tax, insurance and sometimes mortgage insurance into a single monthly figure, and may include an arrangement fee in the rate.
- How much does one percentage point change the payment?
- On a typical 30-year mortgage, one extra percentage point raises the monthly payment by roughly ten per cent and the total interest by considerably more. Run the calculator twice to see it for your own numbers.
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Updated 2026-09-20. Results are estimates for guidance, not financial advice.