UK Debt Avalanche Calculator

The debt avalanche method prioritises debts by highest interest rate (APR) rather than balance size. You pay minimum payments on all debts, then put all extra money toward the debt with the highest APR.

Once that high-interest debt is paid off, you move to the next highest APR debt. This creates an "avalanche" of savings as you eliminate the most expensive debts first. Mathematically it saves the most money - but it's slower to deliver visible wins than snowball.

1. List all your debts with their balance, APR, and minimum payment.
2. Order by APR (highest first) - sort from highest interest rate to lowest.
3. Attack the highest APR - make minimums on all debts, throw extra money at the highest APR debt.
4. Cascade to the next debt - when the first is cleared, roll its payment into the next highest APR.

Avalanche always saves more interest because you clear the most expensive debts first. That part is settled maths. But for a typical UK debt mix, where most cards sit in a similar 18 to 25% APR band, the gap is usually small, often only a few pounds a month.

Snowball has higher completion rates because clearing whole debts quickly keeps you motivated. Avalanche wins on paper. Snowball wins in real life. The best method is the one you actually finish.

Our calculator shows both side by side, so you can see the exact difference for your situation. For a deeper comparison see our snowball vs avalanche guide.

Here's how the avalanche method orders typical UK debts:

• Store card - £1,200 at 29.9% APR (target first)
• Credit card - £3,500 at 21.9% APR (target second)
• Car loan - £8,000 at 6.5% APR (target last)

You'd attack the £1,200 store card first even though it's the smallest, because the 29.9% APR is costing you the most in interest. Snowball would target the same debt for a different reason (smallest balance), but if the smallest debt had a low rate, the two methods would diverge.