What Is an Amortization Schedule? A Simple Guide With Examples
An amortization schedule shows exactly how each mortgage payment splits between interest and principal over the life of your loan. This guide explains what an amortization schedule is, how to read one, and why the early years cost so much interest.
When you take out a mortgage, you make the same payment every month for years — but what that payment does changes dramatically over time. An amortization schedule is the table that reveals exactly how each payment splits between interest and principal, month by month, until the loan is paid off. Understanding it is one of the most eye-opening things you can do as a borrower, and this guide explains it in plain English with a worked example.
You can generate a full amortization schedule for any loan with our UK Mortgage Calculator or US Mortgage Calculator. First, let's understand what the schedule is telling you.
What is an amortization schedule?
An amortization schedule is a complete table of every payment on an amortizing loan — a loan you repay in equal instalments over a fixed term, like a mortgage or car loan. For each payment, the schedule shows four things:
- The payment amount (usually the same every month).
- How much of that payment goes to interest.
- How much goes to principal (the actual loan balance).
- The remaining balance after the payment.
The word "amortize" means to gradually pay off a debt. The schedule simply maps out that gradual process from your first payment to your last.
Why early payments are mostly interest
Here's the part that surprises most borrowers: in the early years, the vast majority of each payment goes to interest, not principal. That's because interest is charged on the outstanding balance, which is at its largest at the start. As the balance slowly falls, less interest accrues, so a bigger slice of each payment starts chipping away at the principal. This is why an amortization schedule shows the principal portion growing every month while the interest portion shrinks.
On a typical 25 or 30-year mortgage, it can take many years before more of your monthly payment goes to principal than to interest.
Worked example: reading an amortization schedule
Suppose you borrow £200,000 over 25 years at 5% interest, giving a monthly payment of roughly £1,169. Here's what the first few rows of the amortization schedule look like:
| Month | Payment | Interest | Principal | Balance |
|---|---|---|---|---|
| 1 | £1,169 | £833 | £336 | £199,664 |
| 2 | £1,169 | £832 | £337 | £199,327 |
| 3 | £1,169 | £831 | £338 | £198,989 |
In month one, £833 of your £1,169 payment is pure interest — only £336 actually reduces what you owe. By the final year of the loan, this is reversed: almost the entire payment goes to principal because the balance (and therefore the interest) is tiny.
How overpayments change the schedule
Because interest is charged on the balance, anything extra you pay goes straight to reducing the principal — which means less interest for the rest of the loan. Even small, regular overpayments can shave years off the term and save a substantial amount of interest. Our mortgage calculators let you add overpayments and instantly see the new, shorter amortization schedule. If you're weighing overpaying against other goals, our guide on how much mortgage you can borrow and the 15-year vs 30-year mortgage comparison are useful companions.
Why the amortization schedule matters
Reading your amortization schedule helps you:
- See the true cost of borrowing — the total interest across the whole term is often eye-watering.
- Decide on overpayments — you can see exactly how much interest each extra payment saves.
- Understand equity — the principal you've repaid is the equity you've built in your home.
- Compare loan terms — a shorter term builds principal faster, as we show in our 15 vs 30-year mortgage guide.
Frequently asked questions
What is an amortization schedule?
It's a table showing every payment on a loan, split into interest and principal, along with the remaining balance after each payment. It maps out exactly how your loan is paid off over its full term.
Why is most of my mortgage payment going to interest?
Because interest is charged on the outstanding balance, which is largest at the start of the loan. Early on, most of each payment covers interest; as the balance falls, more goes to principal.
How do I read an amortization schedule?
Each row is one payment. It shows the payment amount, how much is interest, how much reduces the principal, and the balance left. Over time you'll see the interest column shrink and the principal column grow.
Do overpayments change my amortization schedule?
Yes. Overpayments reduce the principal directly, so less interest accrues for the rest of the loan. This shortens the term and lowers the total interest — you can model it in our mortgage calculators.
Is an amortization schedule the same for all loans?
The principle is the same for any amortizing loan (mortgages, car loans, personal loans), but the numbers depend on the loan amount, interest rate and term. Interest-only loans work differently and don't amortize the principal.
This article was last reviewed in 2026. Figures are illustrative for guidance only and are not financial advice.