Mortgage Calculator
Monthly payment, total interest, and full amortization schedule — plus what extra principal does to your payoff date.
Results
Monthly payment
$0.00
Loan amount
$0
Total paid
$0
Total interest
$0
Payoff in
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How a mortgage payment is built
Each monthly payment is the same total dollar amount for the life of a fixed-rate loan, but the split between interest and principal changes every month. Early on, most of your payment is interest. Years later, most of it goes to principal. The chart above shows this crossover.
Extra principal payments are powerful precisely because they attack the principal directly — and once that principal is gone, you stop paying interest on it for every remaining month. A small extra payment in year 1 saves more than the same payment in year 29.
The formula
- M = monthly payment
- P = loan principal (price minus down payment)
- r = monthly interest rate (annual ÷ 12)
- n = total payments (years × 12)
Amortization schedule
First 12 months, then every 12 months. Export CSV for the full table.
| Month | Payment | Principal | Interest | Balance |
|---|
Frequently asked questions
Does this include taxes, insurance, and PMI?
No. This is principal + interest only (P&I). Property taxes, homeowners insurance, and (if down payment < 20%) PMI add hundreds more per month. Add roughly 25–30% on top for a quick total housing cost estimate.
15-year vs 30-year — which is better?
A 15-year loan has a higher monthly payment but a much lower total interest cost and builds equity faster. A 30-year gives you flexibility — pay extra when you can but drop back to the minimum if life happens. Most people are better off taking the 30-year and making extra principal payments only when comfortable.
How much does one extra payment per year save?
On a 30-year mortgage, one extra principal payment per year typically shaves 4–6 years off the term and tens of thousands in interest. Try setting the extra-monthly field to about 1/12 of your monthly payment to simulate it.