Amortization Calculator
An amortization calculator is a financial tool that computes the periodic payments of a loan and provides a detailed schedule showing how each payment is split between principal and interest. It calculates the remaining principal balance after each payment, demonstrating the gradual reduction of the debt over the loan's life.
Calculate your monthly loan payments, see the principal and interest breakdown, and generate a full month-by-month amortization schedule for any fixed-rate loan.
Quick Answer
See how much of each payment goes to principal vs interest with a full month-by-month amortization schedule for any loan.
The principal borrowed. · e.g. 100,000
Nominal APR. Enter 0 for an interest-free loan. · e.g. 6
Length in years. · e.g. 30
Term is measured in
Payment frequency
Additional principal applied to every payment. · e.g. 100
Adds dates to the schedule and shows a payoff date.
Scheduled monthly payment
$599.55
360 payments
Amortization schedule
360 payments
| # | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $599.55 | $99.55 | $500.00 | $99,900.45 |
| 2 | $599.55 | $100.05 | $499.50 | $99,800.40 |
| 3 | $599.55 | $100.55 | $499.00 | $99,699.85 |
| 4 | $599.55 | $101.05 | $498.50 | $99,598.80 |
| 5 | $599.55 | $101.56 | $497.99 | $99,497.24 |
| 6 | $599.55 | $102.06 | $497.49 | $99,395.18 |
| 7 | $599.55 | $102.57 | $496.98 | $99,292.61 |
| 8 | $599.55 | $103.09 | $496.46 | $99,189.52 |
| 9 | $599.55 | $103.60 | $495.95 | $99,085.92 |
| 10 | $599.55 | $104.12 | $495.43 | $98,981.80 |
| 11 | $599.55 | $104.64 | $494.91 | $98,877.16 |
| 12 | $599.55 | $105.16 | $494.39 | $98,772.00 |
Examples
$300k loan, 30 yr at 7% interest
Payment $1,995.91/mo · 360 payments · total interest ≈ $418,524
Same loan over a 15-year term
Payment $2,696.48/mo · 180 payments · total interest ≈ $185,368
$150k loan, 10 yr at 6% interest
Payment $1,665.31/mo · 120 payments · total interest ≈ $49,837
How it works
The monthly principal and interest portion is computed using the standard amortized loan formula. The calculator then charts the progression of payments to show the principal reduction over time.
Monthly principal and interest
M = P × r × (1 + r)^n / ((1 + r)^n − 1)
The parts
- M = monthly payment
- P = loan amount (principal)
- r = monthly interest rate (annual rate ÷ 12 ÷ 100)
- n = number of monthly payments
What is loan amortization?
Amortization is the process of spreading out a loan into a series of fixed, equal payments over time. With each payment, a portion of the money goes toward interest (the cost of borrowing) and the rest goes toward the principal balance (the amount borrowed). An amortization schedule shows this breakdown for every payment.
How the amortization schedule works
When you first start paying off an amortized loan, the vast majority of each monthly payment goes toward paying off the interest. As the loan matures and the overall principal balance decreases, the monthly interest charge also shrinks. Consequently, a larger percentage of your monthly payment is applied to the principal.
Related amortization tools
For home-specific mortgages or simpler payment calculations, check out these related tools:
Disclaimer. This calculator is for general educational use. Actual loan terms, interest accrual methods, and amortization details can vary by lender, loan type, credit profile, and regional regulations. It is not financial advice.
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