Mortgage Amortization Calculator
Monthly Amortization Schedule
| Month | Payment↕ | Interest↕ | Principal↕ | Balance↕ |
|---|---|---|---|---|
| 1 | $1,498.88 | $1,250.00 | $248.88 | $249,751.12 |
| 2 | $1,498.88 | $1,248.76 | $250.12 | $249,501.00 |
| 3 | $1,498.88 | $1,247.51 | $251.37 | $249,249.63 |
| 4 | $1,498.88 | $1,246.25 | $252.63 | $248,997.00 |
| 5 | $1,498.88 | $1,244.99 | $253.89 | $248,743.11 |
| 6 | $1,498.88 | $1,243.72 | $255.16 | $248,487.95 |
| 7 | $1,498.88 | $1,242.44 | $256.44 | $248,231.51 |
| 8 | $1,498.88 | $1,241.16 | $257.72 | $247,973.80 |
| 9 | $1,498.88 | $1,239.87 | $259.01 | $247,714.79 |
| 10 | $1,498.88 | $1,238.57 | $260.30 | $247,454.49 |
| 11 | $1,498.88 | $1,237.27 | $261.60 | $247,192.88 |
| 12 | $1,498.88 | $1,235.96 | $262.91 | $246,929.97 |
This mortgage amortization calculator generates the complete payment-by-payment schedule for a fixed-rate home loan, listing the interest, principal, and remaining balance for every single month of the term. Unlike a quick payment estimate, the focus here is the full table: it shows exactly how each level payment is split, how the interest share shrinks as the balance falls, and when your equity finally overtakes the lender's interest. Totals for the monthly payment, lifetime interest, and total amount repaid sit on top of the schedule.
Formula
Interestₘ = Balanceₘ · r; Principalₘ = M − Interestₘ; Balanceₘ₊₁ = Balanceₘ − Principalₘ
- M
- Fixed monthly payment = P · r(1+r)ⁿ / ((1+r)ⁿ − 1)
- r
- Monthly interest rate = annual rate ÷ 12 ÷ 100
- Balanceₘ
- Outstanding principal at the start of month m
- Interestₘ
- Interest portion charged in month m
- Principalₘ
- Principal portion repaid in month m
How it works
- Enter the loan amount, annual interest rate, and term in years. The calculator computes the fixed monthly payment with the standard annuity formula, holding that payment constant for the whole term.
- It then walks month by month: each month's interest is the current balance times the monthly rate, the rest of the payment reduces principal, and the balance is carried into the next row. This continues for every month until the balance reaches zero.
- The schedule lists month number, payment, interest, principal, and remaining balance for all payments, while the summary reports total interest paid and the total of all payments over the life of the loan.
Worked example
A $300,000 loan at a 6% annual rate amortized over a 30-year (360-month) term.
- Monthly payment: 300,000 × 0.005 × 1.005³⁶⁰ ÷ (1.005³⁶⁰ − 1) = $1,798.65.
- Month 1: interest = 300,000 × 0.005 = $1,500.00, principal = 1,798.65 − 1,500 = $298.65, balance falls to $299,701.35.
- Month 360: interest is just $8.95, principal is $1,789.70, and the balance reaches $0.
The fixed payment is $1,798.65, total interest over the schedule is $347,514.57, and the total repaid is $647,514.57.
Frequently asked questions
- What is an amortization schedule?
- It is a table that lists every scheduled payment and breaks each one into the interest charged and the principal repaid, tracking the declining balance until the loan is fully paid off. It shows precisely how a fixed payment is allocated over time.
- Why does early-payment interest dwarf principal?
- Interest each month is calculated on the outstanding balance, which is at its largest in the opening months. With a $300,000 loan at 6%, the first payment is mostly interest, and only as the balance shrinks does the principal portion of each fixed payment grow.
- Does this schedule include taxes, insurance, or PMI?
- No. It amortizes only principal and interest on the loan amount you enter. Property tax, homeowners insurance, HOA dues, and private mortgage insurance are escrow or add-on items not reflected in this principal-and-interest schedule.
- How can I use the schedule to plan extra payments?
- By reading the principal column you can see how much balance each payment retires. Any additional amount you pay goes entirely to principal, removing those future interest charges and shortening the schedule, which a dedicated payoff calculator can quantify.