Amortisation calculator
A repayment mortgage charges the same amount each month, but the split inside that payment shifts dramatically. Early on, most of it is interest. Later, most of it is capital. Seeing the schedule year by year explains a great deal about how mortgages behave.
Why the early years feel so slow
Answer first: because interest is charged on the outstanding balance, and early on the balance is at its largest. Your payment is fixed, so when the interest portion is high the capital portion is whatever is left — which is not much.
As the balance falls, the interest charged falls with it, and a growing share of the same payment goes to capital. The effect accelerates. This is why the balance seems barely to move in the first few years and then drops noticeably later, and why overpayments made early are worth so much more than the same sum made near the end.
What the schedule is useful for
Three things. It shows the total interest you are committing to, which is the real price of the loan rather than the monthly figure. It shows how much capital you will have repaid by any given year, which matters for your loan-to-value at remortgage. And it makes the case for overpaying concrete rather than abstract.
On the LTV point specifically: knowing what your balance will be in two or five years tells you which band you are likely to reach, which is worth knowing before you choose how long to fix for.
One honest caveat
The schedule assumes the rate holds for the whole term. It will not. Your deal ends, you re-price, and the figures shift — which is exactly why the later years should be read as illustrative rather than predictive.
What does not change is the shape: interest-heavy early, capital-heavy late. That pattern is worth understanding even though the numbers move. And it is worth knowing that on an interest-only mortgage none of this happens at all — the balance does not amortise, which is a different proposition entirely.
Amortisation, answered
What does amortisation mean?+
It is the gradual repayment of a loan through regular payments that cover both interest and capital. On a repayment mortgage the payment stays level while the split inside it shifts from mostly interest to mostly capital across the term.
Why is so much of my early payment interest?+
Because interest is charged on the outstanding balance, which is at its largest at the start. With the payment fixed, a high interest portion leaves little for capital. As the balance falls the interest falls too, so more of the same payment goes to reducing the debt.
Does the schedule stay accurate?+
Only while the rate holds. Since most people re-price every few years, treat the later rows as illustrative of the shape rather than a forecast of the figures. The pattern is reliable even when the numbers are not.
How does an overpayment change the schedule?+
It reduces the balance immediately, so every subsequent month's interest is calculated on a smaller sum — which shifts more of each future payment to capital and shortens the term. Use the overpayment calculator to size that effect.