Minimum payments are usually set as a percentage of the remaining balance. That single design choice is what turns a manageable-looking debt into one that can outlast the person who took it out.
| Strategy | Time to clear | Total interest |
|---|---|---|
| Fixed £150/month | 2.3 years | £916 |
| Minimum payments only (2.5% of balance) | Still unpaid after 50 years | £13,510+ |
The fixed-payment plan costs £916 in interest — about 31% of the original balance — and is done in just over two years. The minimum-payment simulation, run out to a 50-year cap, has already cost over four and a half times the original balance in interest, with no payoff date in sight.
A percentage-of-balance minimum payment shrinks every single month, in lockstep with the balance it's supposed to be paying down. Early on, most of that shrinking payment still covers interest, leaving only a small sliver for principal — and that sliver keeps getting smaller. It's not a rare edge case; it's the built-in mathematics of how percentage-based minimum payments work on any card at a typical UK APR.
Switching from "pay whatever the minimum happens to be" to a fixed monthly amount — even the same starting figure — changes the entire trajectory, because a fixed payment covers a growing share of principal every month instead of a shrinking one.
Compare a fixed payment plan against the real minimum-payment simulation for your actual balance and APR.
Use the Credit Card Calculator →