See how long it takes to clear a debt or credit card at a fixed monthly payment, and the total interest you'll pay.
Assumes constant interest rate and fixed monthly payment. An estimate — not advice.
Enter the current debt balance, the annual interest rate (APR) and your monthly payment. The calculator simulates month-by-month repayment: each month interest is added and the payment reduces the balance until it reaches zero.
The key insight is how dramatically increasing your payment shortens the payoff time. On a £5,000 debt at 22% APR, paying £150/month takes 46 months and costs £1,867 in interest. Paying £300/month clears it in 19 months for just £674 in interest — less than half the cost and time.
If monthly payment ≤ monthly interest charged, the balance never falls. Increase the payment above the monthly interest.
Most UK cards charge 20–30% APR. Store cards and subprime cards can charge 40%+. Always pay more than the minimum.
Monthly interest = balance × (APR ÷ 12 ÷ 100). The payment first covers interest, then reduces the principal.
No — the calculation runs locally in your browser.
Debt repayment is compound interest running against you. Each month, interest is added to the balance and your payment must first cover that interest before a penny reduces the debt. The calculator above shows the two numbers lenders rarely volunteer: how many months your current payment needs, and how much total interest you will hand over on the way.
The mechanics explain why minimum payments are so dangerous. If your balance is £3,000 at 22% APR, the first month’s interest is about £55. Pay £60 and only £5 reduces the debt — you are almost renting the balance. There is even a mathematical cliff: if the payment is smaller than the monthly interest, the balance grows forever and no payoff date exists. The calculator flags exactly this situation.
A £3,000 credit-card balance at 22% APR, paying £150 a month, takes about 25 months and costs roughly £771 in interest. Raise the payment to £200 and it clears in about 18 months for £540 — £50 more per month buys back seven months of your life and £231 of interest. Small increases early have outsized effects because they cut the balance the interest is charged on.
Card minimums are typically a small percentage of the balance, so they shrink as the balance shrinks — the payment glides down and the payoff date recedes. Fixing your payment at today’s amount (instead of the sliding minimum) alone cuts years off the term.
Keep a small emergency buffer (£500–£1,000) so a broken boiler doesn’t go straight back on the card, then prioritise any debt costing more than your savings earn — which is almost always true for cards and overdrafts.
Cards apply extra payments immediately with no penalty. Personal loans may charge a small early-settlement fee (capped in the UK); even then, overpaying usually wins — check the settlement figure and compare with the interest remaining.