What is the debt avalanche method?
The debt avalanche method is a repayment strategy where you clear debts from the highest interest rate to the lowest, which pays the least total interest possible.
You make the minimum required payment on every debt, then direct all surplus budget at the debt with the highest APR — regardless of its balance. When that debt clears, its payment rolls onto the next-highest rate. Because you always attack the most expensive debt first, no other order costs less in interest.
Debt avalanche vs debt snowball — which is better?
The avalanche is mathematically superior and saves the most interest; the debt snowball is behaviourally superior because clearing small balances first keeps more people motivated.
The debt snowball targets the smallest balance first for quick wins; the avalanche targets the highest rate first for the lowest cost. If one very high-APR card dominates your interest bill and you can stay disciplined, the avalanche is usually the smart choice. Both calculators share the same inputs, and our snowball vs avalanche guide compares them in depth.
Worked example. Say you owe £800 on an overdraft at 9% APR, £4,200 on a credit card at 29.9% APR and £2,500 in car finance at 14% APR, with £150 a month spare. The avalanche attacks the credit card first and makes you debt-free in 27 months for £1,862.21 in interest. The snowball, attacking the £800 overdraft first, takes 29 months and £2,482.32 — so here the avalanche saves about £620 and two months. Enter those figures above to reproduce the result exactly.
How do interest rates affect how much the avalanche saves?
The higher the base rate, the more the avalanche saves — because high APRs make ignoring your most expensive debt costlier.
Lenders price credit off the central bank base rate, which the Bank of England holds at 3.75% as of July 2026. When rates are elevated, the gap between attacking a 30% card and a 9% overdraft first is wider than it was in the near-zero era of 2020–21, so the avalanche's advantage over the snowball grows. Source: Bank of England — Bank Rate (correct as of Sat Jul 25 2026 00:00:00 GMT+0000 (Coordinated Universal Time)).
How does this calculator work?
Enter each debt's balance, APR and minimum payment, add any overpayment, and the tool simulates every month until you are debt-free.
- Enter each debt's balance, APR, and minimum payment (fixed and/or percentage — the higher applies each month).
- Add any extra overpayment you can commit on top of the minimums.
- The tool accrues interest, pays every minimum, then throws all spare cash at the highest-APR debt until it clears — then rolls to the next.
- You get your debt-free date, payoff order, total interest, a balance chart, and a downloadable month-by-month schedule.
Struggling to keep up minimum payments? Get free advice from StepChange or Citizens Advice, and consider the Debt Respite Scheme (Breathing Space), which freezes interest and enforcement for 60 days.