A credit card payoff calculator that shows how many months a fixed monthly payment takes to clear your balance, the total interest you’ll pay, and how much slower and more expensive it is to make only the minimum payment. For anyone tackling card debt and deciding how much to pay each month.
How it works
The tool simulates the balance month by month. Each month it adds interest equal to balance × (APR ÷ 12 ÷ 100), then subtracts your payment; it repeats until the balance reaches zero, counting months and totalling interest. If your payment is less than the first month’s interest, the balance grows and the tool reports that it never clears. For the minimum-payment comparison it pays the greater of 2% of the current balance or a small floor each month — recalculated as the balance falls — which is why minimum payments stretch the debt out for years.
Worked example: fixed vs minimum
A £5,000 balance at 22.9% APR, paying £200/month:
- Cleared in about 2 years 8 months
- Total interest: about £1,400
The same balance on the minimum-payment track (starting at 2% of the balance, falling as the balance falls) takes far longer and costs substantially more. The calculator shows both figures side by side so the gap is impossible to ignore.
| Balance | APR | Payment | Payoff | Interest |
|---|---|---|---|---|
| £2,000 | 19.9% | £100 | ~1y 11m | ~£350 |
| £5,000 | 22.9% | £200 | ~2y 8m | ~£1,400 |
| £5,000 | 22.9% | £150 | ~4y 2m | ~£2,500 |
| £10,000 | 24.9% | £300 | ~4y 2m | ~£5,000 |
Why the minimum payment trap is so severe
The minimum payment is typically set as a percentage of the current balance, so it shrinks every month as the balance falls. That means you are always paying just enough to prevent the lender from declaring default — not enough to make real progress. In the early months of a high-APR card, the minimum payment barely covers the month’s interest. The principal falls by only a few pounds each month, so the balance lingers for years. Setting a fixed payment — even just £30 or £50 above the minimum — breaks this cycle because the payment stays constant while the interest charge falls as the balance falls, so an increasing slice of each payment chips away at the principal.
Common mistakes and edge cases
Paying less than one month’s interest causes the balance to grow, not shrink. The calculator reports this immediately so you know the minimum viable payment before it becomes a problem.
Ignoring new charges is the most common planning error. This calculator models a balance you stop adding to. If you continue spending on the card, the real payoff timeline is longer than shown.
0% balance transfer periods can be modelled by setting the APR to 0 for the promotional months. Remember that most balance transfers carry an upfront fee (typically 1–3% of the transferred amount) that adds to the balance, and the rate jumps to the standard APR once the promotion expires.
Everything is calculated privately in your browser — your balance, APR and payment amount are never uploaded or stored.