Mortgage Calculator (US)
Price, down payment, rate, and term — P&I plus taxes and insurance, live.
How this is calculated
The principal & interest payment amortizes the loan (home price minus down payment) with the standard formula; taxes and insurance ride on top, which is how US lenders quote the full PITI payment:
P&I = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1) then total = P&I + taxes & insurance
Worked example: a $400,000 home with $80,000 down (20% — no PMI) at 6.5% over 30 years borrows $320,000 for a P&I payment of about $2,023 per month; with $350 of taxes and insurance the total is about $2,373. Over the full term that loan pays roughly $408,100 in interest — more than the original principal, which is normal for 30-year money and exactly why the 15-year toggle is worth a look.
The 20% down payment line
The result shows loan-to-value live because 80% is the line that matters: above it, most conventional loans add PMI (roughly 0.3–1.5% of the loan per year) until you reach 20% equity. If your LTV reads over 80%, put a PMI estimate into the taxes-and-insurance field so the total monthly figure stays honest — and know that reaching 80% later lets you request PMI removal rather than paying it for the life of the loan.
Frequently asked questions
How is the monthly payment calculated?
Principal & interest use the standard amortization formula M = P·r(1+r)ⁿ ÷ ((1+r)ⁿ − 1) on the loan (home price minus down payment). The taxes-and-insurance field is added on top so you see the realistic total monthly cost, the way US lenders quote PITI.
What is PMI and does this include it?
Private mortgage insurance — typically required when your down payment is under 20% (LTV above 80%, shown live in the result). It usually runs 0.3–1.5% of the loan per year; if your LTV is above 80%, add an estimate to the taxes-and-insurance field to keep the total honest.
30-year or 15-year — how do I compare?
Flip the term toggle and watch two numbers: the monthly payment (higher on 15) and total interest (dramatically lower on 15 — often less than half). The right answer is the biggest payment you can sustain without risking the rest of your budget.
Why is the quoted APR different from the interest rate?
The rate drives the payment; APR folds in closing costs and points to make offers comparable. Enter the interest rate here (the number the amortization actually uses), and treat APR as a shopping-comparison figure.
Is anything I type sent anywhere?
No — prices, down payments, and rates are computed entirely in your browser and never uploaded. The page works offline once loaded.