10-year loan at 3%
Borrow 100,000 for 10 years at 3% a year. That is 120 monthly payments at a monthly rate of 0.25%.
- Monthly payment
- 966
- Total paid
- 115,920
- Total interest
- 15,920
Mortgage Calculator
Compute the monthly payment on a fixed-rate mortgage from the principal, term, and interest rate. Results also show total payments over the life of the loan and how much of that total is interest.
Enter the amount you plan to borrow, the number of years, and the annual rate. The calculator assumes equal monthly payments that fully repay the loan by the final month — the usual setup for a conventional amortizing mortgage. Figures are theoretical and for information only.
Results
- Monthly payment
- —
- Total payment
- —
- Interest payment
- —
How the monthly payment is calculated
Each month you pay interest on the balance that is still outstanding, plus a slice of principal. Early payments are mostly interest; later payments are mostly principal. The payment itself stays the same if the rate is fixed.
The calculator uses the standard amortization (annuity) formula. The annual rate is converted to a monthly rate by dividing by 12, and the term in years is converted to a number of monthly payments by multiplying by 12:
M = P × r / (1 − (1 + r)−n)
- M — monthly principal-and-interest payment
- P — loan principal (the mortgage amount)
- r — monthly interest rate (annual rate ÷ 12, in decimal form)
- n — number of monthly payments (years × 12)
Total payment is the monthly amount times n. Total interest is that figure minus the original principal. Results are rounded to the nearest whole unit, matching the numbers you see in the results panel. The tool does not add taxes, insurance, or fees.
Worked examples
These three cases use the same formula and rounding as the calculator above. You can type the inputs in and should get the same monthly payment.
30-year loan at 3%
Borrow 300,000 for 30 years at 3%. The monthly payment drops relative to a shorter term, but interest paid over the life of the loan is much larger.
- Monthly payment
- 1,265
- Total paid
- 455,400
- Total interest
- 155,400
15-year loan at 6.5%
Borrow 250,000 for 15 years at 6.5%. A higher rate and a mid-length term sit between the first two cases on monthly cost.
- Monthly payment
- 2,178
- Total paid
- 392,040
- Total interest
- 142,040
Related calculators on this site
Mortgage payments are one way interest rates show up in personal finance. These tools use the same site models if you want to compare a loan with a bond, or put a volatility number on a different time scale.
Mortgage payment FAQ
This calculator uses the standard fixed-rate amortization formula shown above. The annual interest rate is divided by 12 to get a monthly rate, and the term in years is multiplied by 12 to get the number of monthly payments. The monthly payment is then principal times the monthly rate, divided by one minus (1 + monthly rate) raised to the power of minus the number of months.
No. The result is principal and interest only. Property taxes, homeowners insurance, mortgage insurance (PMI), HOA dues, and closing costs are not included, so a lender escrow payment can be higher.
Stretching the same loan over more years lowers the monthly payment because the principal is repaid more slowly. You pay interest for longer, so total interest usually rises. A shorter term does the opposite: a higher monthly payment and less interest over the life of the loan. The 10-year and 30-year examples above show that trade-off.
The formula assumes a fixed interest rate and equal monthly payments for the whole term. For an adjustable-rate mortgage you can still estimate the payment at today's rate, but the payment will change when the rate resets.
Lenders may use a different day-count convention, round differently, add origination fees, or quote an APR that includes points and other costs. Taxes, insurance, and PMI in an escrow account also raise the amount due each month.
The interest rate is the contractual rate applied to the outstanding balance. APR (annual percentage rate) folds in certain upfront fees and points so you can compare the all-in cost of two loan offers. Enter the interest rate here, not the APR, if you want the contractual monthly principal-and-interest payment.
Yes, if the loan is fully amortizing with a fixed rate and monthly payments. Enter the new principal (or the amount you will borrow), the new term, and the offered rate. The tool does not model cash-out costs, prepayment penalties, or remaining life on an existing mortgage.
Disclaimer: the contents of this website are for informational purposes only and do not constitute any investment recommendation. The visitor acts at his own risk.