Mortgage Calculator
Estimate your monthly mortgage payment from home price, down payment, interest rate, and loan term, using the standard amortization formula lenders use for fixed-rate loans. Alongside the monthly principal-and-interest payment, you get total interest paid over the life of the loan, an estimated payoff date, and a year-by-year amortization breakdown for the first few years showing how much of each payment goes to principal versus interest. This is a planning tool for principal and interest only — it does not include property taxes, homeowners insurance, PMI, or HOA dues, all of which typically add to your actual monthly housing cost. Everything runs in your browser; nothing you enter is sent anywhere.
By The Paper Room Editorial Team — Financial & Utility Tools
Frequently asked questions
What's the difference between interest rate and APR?▼
The interest rate is what you pay on the principal balance each year. APR (annual percentage rate) also folds in lender fees and closing costs, so it's usually slightly higher — APR is the better number for comparing offers from different lenders, but the plain interest rate is what this calculator uses to compute your monthly principal-and-interest payment.
Does this include property tax and homeowners insurance?▼
No — this calculates principal and interest (P&I) only, which is what the standard amortization formula covers. Property taxes, homeowners insurance, PMI (if your down payment is under 20%), and HOA dues are separate and vary by location, so your actual monthly payment (often called PITI) will be higher than the number shown here.
What's a good down payment percentage?▼
20% avoids private mortgage insurance (PMI) on a conventional loan and lowers your monthly payment, but many buyers put down less — conventional loans often allow as low as 3-5%, and FHA loans allow 3.5%. A smaller down payment means a larger loan, a higher monthly payment, and (below 20%) added PMI cost until you build enough equity.
Why does so much of my early payments go to interest?▼
Amortizing loans front-load interest because it's calculated on the remaining balance each month, and the balance is highest at the start. As you pay down principal, the interest portion of each payment shrinks and the principal portion grows — you can see this shift in the year-by-year table above.
How much does an extra principal payment save?▼
Any extra amount applied directly to principal reduces the balance interest is calculated on for every remaining month, which shortens the loan and cuts total interest — even small, consistent extra payments early in the loan can save thousands over 30 years. This calculator doesn't model extra payments directly, but you can approximate the effect by shortening the loan term field.