Debt Avalanche Calculator
This debt avalanche calculator shows the mathematically fastest, cheapest way to become debt-free: pay minimums on everything, and throw every extra dollar at your highest-interest-rate debt first. Enter up to three debts to see your payoff timeline and total interest.
Leave later slots at £0 if you have fewer than three debts.
The annual percentage rate charged on this balance.
The smallest monthly payment this lender requires.
Set to £0 if you don't have a debt in this slot.
The annual percentage rate charged on this balance.
The smallest monthly payment this lender requires.
Set to £0 if you don't have a debt in this slot.
The annual percentage rate charged on this balance.
The smallest monthly payment this lender requires.
Money you can put toward debt beyond the minimums, all directed at your highest-rate balance first.
Months to debt-free
32
How long until every listed debt reaches £0, following the avalanche order.
How to use this debt avalanche calculator
- 1Enter each debt's balance, interest rate and minimum payment — leave a slot at £0 if you only have one or two debts.
- 2Extra monthly payment: any amount above the combined minimums that you can commit to debt payoff each month.
- 3The calculator orders your debts highest-rate-first and cascades your extra payment (plus freed-up minimums) onto the next debt each time one is cleared.
Understanding your results
Months to debt-free counts from today until every listed balance reaches zero, following the avalanche order. Interest saved and months saved compare that outcome against paying only the minimums on each debt independently — the avalanche method minimizes total interest paid, which is what makes it the cheaper option compared to the debt snowball whenever your rates differ meaningfully.
The formula
Pay minimums on everything, throw every extra dollar at the highest interest rateEach month, every debt accrues interest and receives its minimum payment. Any money left over — your extra payment, plus the minimums freed up from debts you've already cleared — goes entirely toward the debt with the highest interest rate, regardless of its balance. Because interest is what actually costs you money, eliminating the most expensive rate first minimizes the total interest paid across the whole payoff period.
A worked example
Two debts: a $3,000 balance at 22% APR (min $90) and an $8,000 balance at 18% APR (min $200), with $150 extra a month. The avalanche targets the 22% debt first even though it's the smaller balance — every dollar of interest avoided there is worth more than the same dollar applied to the 18% debt. Once it's cleared, its $90 minimum plus the $150 extra roll onto the $8,000 balance.
Notes for the UK, US and India
The avalanche method is the cost-minimizing choice whenever your debts carry meaningfully different interest rates — the bigger the rate gap, the more it saves versus the snowball method. When your rates are all similar, the two methods produce nearly identical results, and the snowball's early psychological win may be worth the negligible cost difference.
Frequently asked questions
How much more does avalanche actually save versus snowball?+
It depends on how spread out your interest rates are. With a wide gap (e.g. a 24% card versus a 6% loan), avalanche can save hundreds of dollars in interest. With similar rates across debts, the savings shrink to nearly nothing, and the order barely matters.
What if two debts have the same interest rate?+
Order between them doesn't affect total interest — pick whichever motivates you more, such as the smaller balance for an early win.
Should I include a 0% promotional-rate card in this calculator?+
Only for the months the 0% rate actually applies — treat any card that reverts to a standard rate later as a separate debt with its post-promo rate, or use the balance transfer calculator to model the promo period specifically.