Enter up to five debts and a total monthly budget to compare two popular payoff methods side by side: smallest balance first (snowball) and highest interest rate first (avalanche).
Results are estimates for planning. Check the figures before you make a financial or health decision.
How the Debt snowball vs avalanche calculator works
Both strategies are simulated month by month. Each month, interest is added to every debt at APR ÷ 12. Then every debt gets its minimum payment, and the rest of your budget goes to a single target debt. When the target is cleared, its freed-up money rolls onto the next one.
- Snowball targets the smallest current balance.
- Avalanche targets the highest APR.
Results show months to debt-free, total interest, the order each debt is cleared and the difference between methods. Debts with a zero balance are ignored.
If your budget is lower than the minimums combined, the tool shows an error rather than a result. It assumes no new borrowing, fees or changes in rate, and payments at the end of each month. Debts that never clear within 100 years produce a message instead.
Worked example
Using the default values in the calculator above:
| Input | Value |
|---|---|
| Number of debts | 3 |
| Total monthly budget for debt | £600 |
| Debt 1 balance | £1200 |
| Debt 1 APR | 9.9 % |
| Debt 1 minimum payment | £35 |
| Debt 2 balance | £4200 |
| Debt 2 APR | 24.9 % |
| Debt 2 minimum payment | £105 |
| Debt 3 balance | £8000 |
| Debt 3 APR | 6.9 % |
| Debt 3 minimum payment | £160 |
Interest saved by avalanche: £168.06 less interest with avalanche
| Snowball: debt-free in | 2 years 2 months (26 months) |
|---|---|
| Snowball: total interest | £1,659.92 |
| Snowball: payoff order | Debt 1 (month 4), Debt 2 (month 15), Debt 3 (month 26) |
| Avalanche: debt-free in | 2 years 1 month (25 months) |
| Avalanche: total interest | £1,491.86 |
| Avalanche: payoff order | Debt 2 (month 12), Debt 1 (month 14), Debt 3 (month 25) |
Tips and common mistakes
Use the budget you can really sustain, and keep it the same when a debt is cleared so the payment rolls on. Minimums must be the lender’s required amounts. Avalanche usually costs less interest, and snowball can feel faster because early debts disappear sooner. If the totals are close, pick the method you will stick with. Check for promotional or 0% balances, early repayment charges and secured debts such as a mortgage, which need separate thought. If you are struggling, free debt advice is available from charities and MoneyHelper.
Frequently asked questions
Is the avalanche or snowball method better?
Avalanche usually costs less interest than snowball on the same budget, and never more when minimums cover the interest. Snowball can help motivation by clearing small balances quickly. The calculator shows the difference for your numbers.
What happens when my budget is below the minimum payments?
The calculator shows an error and asks for a higher budget. Paying less than the minimums would mean missing payments, which can bring fees and damage your credit record.
Can I add more than five debts?
Not here. You can combine similar small debts into one line, using the total balance, an average APR and the combined minimum, for a close estimate.
Guides that help
- Debt snowball vs avalanche: which method suits you?
- Credit card interest explained: APR, minimums and payoff time
- Loans, APR and car finance: comparing the real cost