What amortisation means for your loan

Resources · Cards, loans and credit · 4 min read Advanced

Key points

• Amortisation (amortization in US spelling) means paying off a loan in regular instalments over a set term.
• Each payment covers that month’s interest. Whatever’s left pays down the balance.
• The payment stays the same, but the split shifts from mostly interest to mostly balance.
• An amortisation schedule shows that split for every single payment.

Here’s amortization explained in one line. You pay a loan down to zero with equal payments, and each one clears the month’s interest and chips away at the balance. The payment is set at exactly the amount that hits zero at the end of the term.

Most personal loans, car loans and home loans work like this. Credit cards usually don’t, because the balance and the minimum payment move around from month to month.

Amortization explained with one loan

Let’s follow one loan from the first payment to the last. The same maths works in any currency.

Assumptions:

• Loan: $20,000
• Interest rate: 8% a year, fixed (monthly rate = 8% ÷ 12)
• Term: 5 years (60 monthly payments)
• Interest charged on the balance each month before the payment
• The last payment is whatever clears the balance

The monthly payment comes to $405.53.

Month 1. Interest is $20,000 × 8% ÷ 12 = $133.33. The other $272.20 goes off the balance, leaving $19,727.80.

Month 2. Now interest is charged on $19,727.80, so it’s a touch lower at $131.52. That means a touch more, $274.01, goes to the balance.

Month 60. Interest is just $2.68. The final payment of $405.35 clears the loan.

Total interest over five years: $4,331.62.

Reading an amortisation schedule

A schedule is a table with one row per payment. Lenders often provide one, and loan calculators can make one for you. The columns usually look something like this:

Run your eye down the interest column and the numbers shrink. Down the balance repaid column, they grow. The payment itself hardly moves.

Why the early years feel slow

Here’s the same loan, grouped by year:

Halfway through, after 30 payments, you still owe $10,993.31. That’s more than half the original loan. And over a third of all the interest gets paid in year one.

It isn’t a trick. Interest is charged on what you owe, and at the start you owe the most. Stretch the loan out to 25 or 30 years, like many home loans, and the effect gets much stronger. Our guide to how a home loan repayment works shows that version.

Loans that don’t follow the usual pattern

Not every loan amortises this neatly.

With an interest-only loan, you pay just the interest for a period. The balance doesn’t budge until full repayments start. A balloon loan keeps payments lower by leaving a big lump sum owing at the very end.

Then there’s negative amortisation. Here the payment is less than the interest, so the unpaid interest gets added on and the balance grows. If that sounds like one of your debts, read when repayments don’t cover the interest.

On a variable rate, the schedule gets recalculated whenever the rate changes. Either the payment moves or the term does.

What changes the schedule

A schedule is a forecast. It assumes the loan goes exactly to plan.

Pay extra, where the loan allows it, and that money comes straight off the balance. Every month after that carries less interest, and the loan finishes sooner unless the payment gets recalculated. Miss a payment or pay less, and interest keeps building anyway, sometimes with fees on top. A rate change on a variable loan shifts things too. So do fees added to the balance.

Some people like to check their schedule once a year to see where they’re up to. Others would rather not look too often. Do whatever keeps you steady.

Common questions

What does amortization mean in simple terms?

Paying off a loan bit by bit with regular payments. Each one covers the interest due and knocks some off the balance, until the balance reaches zero.

Why is most of my payment going to interest?

Early on, the balance is at its highest, so the interest charge is too. As the balance falls, more of each payment goes to the debt itself.

Is amortisation the same in every country?

The maths is the same everywhere. What changes is the kinds of loans on offer, how rates are set and which fees apply.

Try it

Put your own loan into the loan repayment calculator to see the payment and the total interest. Want to see all your debts together? Find your Freedom Date.

General information only, not financial advice. Your situation is your own.