What does an amortization schedule show?

It lists every scheduled payment over the life of a loan, showing how much of each payment goes to interest versus principal and how the outstanding balance falls to zero. Early payments are mostly interest; later ones are mostly principal.

How do extra payments change the schedule?

Any amount you add each month goes straight to the principal, so the balance falls faster, the loan clears sooner and you pay less total interest. Enter an extra amount and the payoff time and total interest update instantly.

Why is so much of my early payment going to interest?

Interest is charged on the outstanding balance, which is largest at the start. So early payments are mostly interest and little principal; as the balance falls, the split flips and most of each payment clears principal.

How is each row in the table calculated?

For every month the tool charges interest equal to balance × (annual rate ÷ 12), subtracts that from the fixed payment plus any extra to get the principal portion, then reduces the balance by that principal. The process repeats until the balance reaches zero.

What is the difference between amortization and a simple interest loan?

An amortizing loan has a fixed total payment split between interest and principal that shifts over time, fully clearing the balance by the end. A simple-interest loan charges interest only on the original principal and is not paid down this way.

Does the schedule work for mortgages, car loans and student loans?

Yes — any fixed-rate, fully amortizing loan with equal monthly payments. Just enter the balance, rate and remaining term. It does not model variable rates, payment holidays or interest-only periods.

Is my loan data sent anywhere?

No. The entire schedule is generated by JavaScript in your browser. No figures are uploaded, stored or shared.

Amortization Schedule Generator

An amortization schedule generator that builds a complete month-by-month payment table for any fixed-rate loan or mortgage. Each row splits the payment into interest and principal and shows the falling balance — so you can see precisely how a loan is paid down, and how an extra monthly payment shortens the term. For borrowers comparing offers, planning overpayments, or checking a lender’s figures.

How it works

First the fixed monthly payment is set with the amortising formula M = P · r(1+r)ⁿ ⁄ ((1+r)ⁿ − 1), where r is the monthly rate (annual rate ÷ 12 ÷ 100) and n is the term in months. Then the tool walks month by month:

Interest = current balance × monthly rate
Principal = (fixed payment + any extra) − interest
New balance = balance − principal

It repeats until the balance hits zero, totalling the interest and counting the months to get the payoff time. Early rows are interest-heavy; later rows are principal-heavy.

Example

A £200,000 loan at 5.5% over 25 years has a payment of about £1,228/month:

Month 1: interest ≈ £917, principal ≈ £311, balance ≈ £199,689
Total interest over 25 years: about £168,000

Add £200 extra each month and the loan clears in roughly 20 years, cutting total interest by around £40,000.

Month	Payment	Interest	Principal	Balance
1	£1,228	£917	£311	£199,689
120	£1,228	£676	£552	£146,900
300	£1,228	£6	£1,222	£0

Everything is calculated in your browser; no loan details ever leave your device.