Mortgage Calculator
Estimate a monthly principal-and-interest payment.
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Enter a home price, down payment, annual rate, and years. The payment shown is an estimate of principal and interest only. It is not a lender quote.
How to use this tool
- Enter the amounts. Fill in principal, rate, term, or prices. Use the same currency throughout.
- Read the estimate. The figures are a simplified model, not a lender or tax quote.
- Compare a related tool. Open amortization, compound interest, or paycheck if you need another view.
The payment formula
For a fixed rate, the monthly principal-and-interest amount is M = P × r × (1+r)^n / ((1+r)^n − 1). P is the loan amount (price minus down payment), r is the monthly rate (annual percent divided by 12 and by 100), and n is the number of months. A zero rate splits the principal evenly.
What is left out
Homeowners insurance, property tax, HOA dues, PMI, discount points, and closing costs are not inside that formula. There is an optional monthly cash field so you can add those estimates yourself. A lender will underwrite with their own taxes, insurance, and credit overlays.
Fixed vs adjustable
This page treats the rate as fixed for the whole term. An ARM that resets after 5 or 7 years is a different product. Do not use this estimate as the payment after a reset.
When to open amortization instead
If you need month-by-month principal versus interest, or you want to see how extra principal changes the payoff date, use the loan amortization table. This page is for a single monthly number.
Frequently asked
Is this a pre-approval?
No. It is an estimate. Talk to a licensed lender for a quote.
Does extra principal shorten the loan here?
The extra field is added to the displayed total monthly cash. For a full payoff schedule, use loan amortization.
Are ARM rates modeled?
No. The rate is treated as fixed for the term you type.
Which compounding is used?
Standard US-style monthly amortization. Other countries may use different conventions.
Can I treat this payment as a lender quote?
No. It is an estimate. A licensed lender has to underwrite the loan.
Does a larger down payment change the rate?
This tool does not pick a rate. You type the rate. In the market, a larger down payment can change pricing and PMI, but that is outside this estimate.
Is PMI included?
Not automatically. If you expect PMI, add it in the extra monthly field.