Debt Snowball vs Avalanche Calculator
Compare two ways of paying off several debts with the same monthly budget: smallest balance first, or highest interest rate first.
Add each debt with its balance, interest rate and minimum payment, plus any extra you can put towards them each month. Calculated in your browser — nothing is saved or sent.
Snowball vs avalanche
Payoff order
When each debt would be cleared under each strategy, and the interest it would cost along the way.
Total debt over time
Your combined remaining balance each month under each strategy. Both spend exactly the same amount every month.
Month-by-month plan
What to pay on each debt every month, and what’s left afterwards.
How the two strategies work
Both strategies pay the minimum on every debt each month and put everything else towards one target debt. When the target is cleared, its minimum payment is “rolled over” — added to the money going to the next target — so the amount attacking your debts grows as each one disappears. The only difference is the order:
- Snowball: smallest balance first. You clear individual debts sooner, which some people find keeps them motivated.
- Avalanche: highest interest rate first. Expensive debt is cleared first, so it usually costs less interest overall — and never more.
How the simulation allocates each month’s money
- Interest is added to every open balance, rounded to the nearest penny.
- Every open debt receives its minimum payment, or its whole balance if that’s smaller.
- The rest of the monthly budget — your extra amount plus minimums freed up by debts already cleared — goes to the top-priority debt, then the next, until it’s used up.
The total monthly budget is your minimum payments added together plus the extra, and both strategies spend exactly that every month until the final one, when only what’s left is paid. That keeps the comparison fair: any difference comes from the order alone. The order is set from your starting balances and rates. Ties are broken consistently — for the snowball, the higher rate goes first; for the avalanche, the smaller balance — and then by the order you listed the debts.
When the results are identical
If your smallest debt also has the highest rate, both methods target the same debts in the same order and produce the same result. The difference also shrinks when debts have similar rates or when your extra payment is large compared with your balances.
Limitations
- Minimum payments are treated as fixed. Credit card minimums usually fall as the balance falls; most loans have a fixed payment.
- Rates are assumed constant. Promotional 0% periods ending, variable rates, fees and charges aren’t modelled.
- Lenders calculate interest differently — often daily, on statement dates — so real figures will differ somewhat.
- If a debt’s minimum payment doesn’t cover its own interest, the calculator flags it. It can still be cleared if extra money reaches it in time; if your total budget can’t outpace the interest, the calculator says so rather than producing a plan.
For a single debt, the Debt Repayment Calculator shows the payoff date and the effect of extra payments in more detail.
Sources
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MoneyHelper
Free, impartial money and debt guidance backed by the UK government, including help finding free debt advice.
Frequently asked questions
Which saves more money, snowball or avalanche?
The avalanche method — highest interest rate first — gives the lowest total interest for a fixed monthly budget, and it is never worse than the snowball. The snowball can still be a reasonable choice if clearing smaller debts quickly helps you stick with the plan.
Why do both strategies show the same result?
That happens when the debt with the smallest balance also has the highest interest rate, so both methods pay debts off in the same order. It can also happen with only one debt, or when the extra payment is large enough to clear the debts almost immediately.
What if a minimum payment doesn’t cover the interest?
The calculator warns you about that debt. If the extra money reaches it soon enough it can still be cleared, but if your total monthly budget doesn’t exceed the interest being added across all your debts, no plan is shown — you would need to increase your payments or seek free debt advice.
Should I include my mortgage or student loan?
You can include any debt, but long-term secured or income-linked debts behave very differently from credit cards and personal loans. Student loan repayments, for example, depend on income rather than a minimum payment, so most people leave them out.
How should I enter a 0% credit card?
Enter 0% as the rate. Bear in mind the calculator assumes the rate stays at 0% until the debt is cleared; if the promotional period will end first, the real cost will be higher than shown.