US Mortgage Calculator
Work out your monthly mortgage payment, add property tax and homeowners insurance, and see how much interest you pay over the life of the loan. You choose the rate: we never assume one.
Calculated in your browser. Nothing you type is sent anywhere.
Optional
Enter the rate quoted by your lender. We do not assume one.
Optional. Check your county tax bill.
Optional.
Optional. Goes straight to principal.
Enter the amount and your interest rate to see the payment.
Nothing is calculated until you give a rate. Use “Load an example” to see how the page works.
Indicative estimate, not financial or tax advice.
How the calculation works
A US fixed-rate mortgage is repaid in equal monthly installments. The calculator turns your annual interest rate into a monthly rate (the rate divided by 12), then finds the installment that clears the loan exactly after the last payment. This is the standard annuity formula: payment = loan × r ÷ (1 − (1 + r)^−n), where r is the monthly rate and n the number of months.
Each payment is split in two. The interest part is the monthly rate applied to what you still owe; the rest reduces the principal. Early on the balance is large, so most of the payment is interest. Every payment lowers the balance, so the interest part shrinks and the principal part grows. The schedule and chart show that shift year by year.
Property tax and homeowners insurance are added on top of principal and interest if you enter them, which is how many lenders collect them through an escrow account. An extra monthly payment goes entirely to principal, so the loan ends sooner and the interest total falls. The calculator shows the interest you save compared with no extra payment.
Worked example
A $400,000 home with $80,000 down (20%) leaves a $320,000 loan. We use 5% over 30 years only to illustrate the arithmetic. It is not a current market rate. Property tax is $4,800 a year and insurance $1,500 a year.
- Principal and interest, per month
- $1,717.83
- Property tax and insurance, per month
- $525.00
- Total monthly payment
- $2,242.83
- Interest paid in the first 12 months
- $15,892.78
- Total interest over 30 years
- $298,418.37
Try the same numbers above with the Load an example button, then replace the rate with your lender’s quote.
Short glossary
- Principal
- The amount you borrowed and still owe, not counting interest.
- Amortization
- Paying a loan off in scheduled installments so the balance reaches zero at the end of the term.
- Escrow
- An account your servicer may use to collect property tax and insurance with each mortgage payment and pay those bills for you.
- Down payment
- The part of the price you pay up front. The rest is the loan.
- Loan term
- The number of years over which the loan is scheduled to be repaid, commonly 15 or 30.
- Interest rate
- The yearly cost of borrowing, stated as a percentage of the balance. This is not the same as the APR, which also reflects some fees.
What this calculator does not do
- No tax or rate tables are used: the rate, property tax and insurance are your own inputs.
- Private mortgage insurance, HOA dues, closing costs, adjustable rates and points are not modeled.
- Payments are assumed monthly, in arrears, with a constant rate for the whole term.