Amortization Calculator
Build a full amortization schedule for any fixed-rate loan or mortgage — month-by-month with real calendar payment dates, total interest, and the payoff date, including the effect of extra monthly payments.
Optional — see how overpaying shortens the loan
Amortization schedule
| Year | Paid | Interest | Principal | Balance |
|---|---|---|---|---|
| 1 | $22,754.40 | $19,401.28 | $3,353.12 | $296,646.88 |
| 2 | $22,754.40 | $19,176.72 | $3,577.68 | $293,069.20 |
| 3 | $22,754.40 | $18,937.11 | $3,817.29 | $289,251.91 |
| 4 | $22,754.40 | $18,681.46 | $4,072.94 | $285,178.97 |
| 5 | $22,754.40 | $18,408.69 | $4,345.71 | $280,833.26 |
| 6 | $22,754.40 | $18,117.65 | $4,636.75 | $276,196.51 |
| 7 | $22,754.40 | $17,807.10 | $4,947.30 | $271,249.21 |
| 8 | $22,754.40 | $17,475.78 | $5,278.62 | $265,970.59 |
| 9 | $22,754.40 | $17,122.27 | $5,632.13 | $260,338.46 |
| 10 | $22,754.40 | $16,745.08 | $6,009.32 | $254,329.14 |
The amortization formula
The fixed monthly payment on a fully amortizing loan is calculated as:
Where M is the monthly payment, P is the principal, r is the monthly interest rate, and n is the number of payments. For example, a $300,000 loan at 6.5% APR over 30 years starting July 2026 has a monthly payment of $1,896.20, with $382,637 of interest paid in total by the payoff date of 2056-06-01.
Frequently asked questions
What is an amortization schedule?
An amortization schedule breaks down every payment on a loan into the interest and principal portions, showing how the balance declines over time. Early payments are mostly interest; later payments are mostly principal — even though the total payment stays the same.
Why does the interest portion shrink over time?
Interest is charged each period on the outstanding balance. As you pay down principal, the balance shrinks, so less interest accrues — meaning a larger share of each fixed payment goes toward principal as the loan matures.
How do extra payments affect the schedule?
Extra payments go straight to principal, which reduces the balance the very next period's interest is calculated on. This compounds over the life of the loan, often saving far more in interest than the extra payment itself, and shortening the payoff date.
Does this work for mortgages, auto loans, and personal loans?
Yes — any fixed-rate, fully amortizing loan uses the same math. Enter the loan amount, rate, and term, and this calculator builds the same schedule a lender would use, with real calendar payment dates.