Mortgage Calculator – Monthly Payment & Loan Amortization
Enter the loan details to see your monthly payment, total interest, and a simple amortization summary.
Planning a home purchase starts with knowing the monthly payment. This mortgage calculator estimates principal-and-interest from loan amount (or price minus down payment), annual rate, and term — plus total interest and total cost over the life of the loan.
Payments use the standard fixed-rate amortization formula: monthly rate r = annual ÷ 12, and n = years × 12. At 0% interest, payment is simply principal ÷ n. The amortization summary shows how the first payment splits between interest and principal, and how that shifts by the final payment.
Taxes, insurance, and PMI are not included. For wage and overtime estimates while budgeting, try the Overtime Calculator. Math runs in your browser.
How to use
- Enter the home price or loan amount, annual interest rate, and term in years.
- Optionally add a down payment — the loan principal updates automatically.
- Read the monthly payment, total interest, and total cost.
- Scan the amortization summary for how much goes to interest vs. principal early on. Use Reset to clear.
Tips
- This estimate uses a fixed-rate amortizing loan formula. Taxes, insurance, HOA, and PMI are not included unless you fold them into the loan amount yourself.
- A larger down payment lowers principal and monthly payment — and may help you avoid PMI.
- Compare lenders on APR as well as rate; fees can change the true cost.
- Extra principal payments shorten the schedule and cut total interest — this tool shows the base schedule without extras.
FAQ
How is the monthly mortgage payment calculated?
For a fixed-rate loan: M = P × [r(1+r)^n] ÷ [(1+r)^n − 1], where P is principal, r is the monthly interest rate (annual ÷ 12), and n is the number of months. A 0% rate uses simple division: P ÷ n.
What is included in this monthly payment?
Principal and interest only (P&I). Property tax, homeowners insurance, HOA dues, and PMI are not added automatically.
How does the down payment work?
If you enter a home price and down payment, principal = price − down payment. If down payment is blank or zero, the loan amount field is used as principal.
What is amortization?
Amortization is how each payment splits between interest and principal over time. Early payments are mostly interest; later ones pay down more principal. The summary here shows first-month and last-month splits plus totals.
Is this quote accurate enough to decide on a loan?
It matches standard fixed-rate amortization math for P&I. Your lender’s quote may differ because of fees, escrow, points, or rate locks. Use this for planning, then confirm with a lender.
What rate should I enter?
Enter the annual interest rate as a percent (for example, 6.5 for 6.5%). Do not enter APR with fees unless you intentionally want that estimate.