The debt snowball pays off your smallest balance first, while the debt avalanche pays off the highest interest rate first. In both, you pay the minimum on every debt and put all spare money on one target. Avalanche normally saves more interest; snowball can feel quicker because small debts vanish early.
How both methods work
The steps are the same except for the choice of target.
- List every debt with its balance, APR and minimum payment.
- Decide a total monthly budget for debt. It must be at least the sum of the minimums.
- Pay every minimum, then send all remaining money to the target debt.
- When the target is cleared, add its payment to the next target. The payment “rolls” forward.
The only difference is the order. Snowball goes smallest balance to largest. Avalanche goes highest APR to lowest.
A worked example
Take three debts and a budget of £600 a month.
| Debt | Balance | APR | Minimum |
|---|---|---|---|
| Debt 1 | £1,200 | 9.9% | £35 |
| Debt 2 | £4,200 | 24.9% | £105 |
| Debt 3 | £8,000 | 6.9% | £160 |
The minimums total £300, so £300 a month is spare. Using the Debt snowball vs avalanche calculator calculator, with interest at APR ÷ 12 and payments at month end:
| Method | Debt-free in | Total interest | Order cleared |
|---|---|---|---|
| Snowball | 26 months | £1,659.92 | Debt 1, Debt 2, Debt 3 |
| Avalanche | 25 months | £1,491.86 | Debt 2, Debt 1, Debt 3 |
Avalanche saves £168.06 and one month. Snowball clears the first debt in month 4; avalanche takes until month 12 for its first, though the debt it clears is the expensive 24.9% one.
With a tighter budget of £450 a month, the gap widens: snowball takes 36 months and £2,498.21 of interest; avalanche takes 35 months and £2,234.48. The longer a debt takes, the more the rate matters.
When snowball can be the better choice
The numbers favour avalanche, but behaviour counts as well. Paying off a debt completely removes a payment and a statement, which can make it easier to keep going. If your debts have similar rates, the interest difference is small and snowball costs little extra. If the rates differ widely, as in the example, avalanche is worth the wait.
The best method is one you will keep following until the last debt is gone. Quitting after a few months costs more than any ordering choice.
Choosing a budget that holds up
The budget is the figure that matters most. Start from what you can pay every month without borrowing again, and keep it fixed even as individual debts disappear. If you cut the payment when the first debt is cleared, you lose the rolling effect that makes both methods work.
It also helps to review the plan every few months. If your income changes or a promotional rate ends, rerun the numbers with the current balances and rates and see whether the target order should change.
Things the calculator leaves out
- No new borrowing. Adding purchases to a card works against any plan.
- Promotional rates. A 0% balance transfer changes the order, so use the real rate on each balance.
- Fees and early repayment charges. Check your agreement.
- Secured debt. A mortgage or car finance has different risks and terms. See Loans, APR and car finance: comparing the real cost.
Interest on a card balance compounds, which is why high rates hurt so much. Compound interest explained, with examples explains the effect, and the same logic in reverse is in How long to reach a savings goal.
Note: This is general information, not financial advice. If you are struggling with debt, free help is available from charities and MoneyHelper.
Try the calculator
Enter up to five debts and your monthly budget in Debt snowball vs avalanche calculator to compare both methods. For a single card, Credit card payoff calculator shows the time to clear and the cost of paying only the minimum.
Open the free Debt snowball vs avalanche calculator
Worked example 2: a high-rate card and a 0% balance
Not every case is close. Take two debts and a budget of £400 a month.
| Debt | Balance | APR | Minimum |
|---|---|---|---|
| Card | £3,000 | 29.9% | £75 |
| Store plan | £900 | 0% | £30 |
The minimums total £105, so £295 is spare. Using the debt payoff calculator with interest at APR ÷ 12:
| Method | Debt-free in | Total interest | Order cleared |
|---|---|---|---|
| Snowball | 12 months | £568.83 | Store plan (month 3), card (month 12) |
| Avalanche | 11 months | £393.47 | Card (month 10), store plan (month 11) |
Avalanche saves £175.37 and a month. Snowball wastes money here because it spends the first three months clearing a debt that charges no interest, while the 29.9% card keeps growing. This is the clearest case for avalanche: a big gap between the rates and a small balance on the cheap debt.
Comparing the two examples
| Feature | Example in the guide above (3 debts, £600) | Example 2 (2 debts, £400) |
|---|---|---|
| Interest saved by avalanche | £168.06 | £175.37 |
| Months saved | 1 | 1 |
| Rate gap between debts | 6.9% to 24.9% | 0% to 29.9% |
The months saved are small in both cases. What changes is how much interest you pay on the way, and that depends on how far apart the rates are and how large the expensive balance is. If you are not sure which situation you are in, run both methods in the calculator and compare the two interest totals before you decide.
Why the extra payment matters more than the method
In both worked examples the method changed the total interest by a few hundred pounds at most, but the size of the monthly budget changed the outcome far more. Raising the budget in the first example from £450 to £600 cut the time from 35 or 36 months to 25 or 26. That is a bigger effect than choosing avalanche over snowball. If you find an extra £25 or £50 a month, for instance by cancelling a subscription you do not use, put it on the target debt and rerun the calculator to see the new finish date.
Windfalls work the same way. A tax refund or bonus put on the target debt reduces the balance that interest is charged on straight away, so it is worth more than the same sum spread over a year. Check whether your lender charges for early repayment first, which is more common on loans than on cards.
Which method for which situation
| Situation | Method that usually fits |
|---|---|
| One debt has a much higher rate than the rest | Avalanche |
| Rates are all similar | Either; choose the one you will stick with |
| You have several tiny balances and feel overwhelmed | Snowball, or a quick win then avalanche |
| A 0% offer is about to end on one balance | Run both with the new rate and compare |
| Your budget barely exceeds the minimums | Avalanche, since interest is a bigger share of each payment |
Step by step: working out your own plan
- Gather the statements. Write down the balance, APR and minimum for each debt, using the figures from this month’s statement.
- Check the promotional rates. Note the date any 0% offer ends and what rate applies afterwards.
- Set the budget. Use the sum you can afford every month after essentials. Keep it above the combined minimums.
- Run both orders. Enter the debts into the calculator and note the interest and the number of months.
- Pick one and automate. Set direct debits for the minimums and a standing order for the extra to the target debt.
- Review every few months. Update the balances and, if a rate changes, rerun the numbers.
Common mistakes
- Cutting the payment when a debt is cleared. The released payment should roll onto the next target, otherwise you lose the momentum.
- Missing a minimum while chasing the target. Late fees and penalty rates can wipe out the saving.
- Ignoring a rate that is about to change. A 0% balance can jump to a high rate on a set date.
- Adding new spending to a card you are paying off. It undoes the work.
- Treating the calculator as a promise. It assumes constant rates and steady payments. Real accounts vary.
Other options to consider
A balance transfer card or a lower-rate consolidation loan may reduce the cost, but fees, eligibility and what happens when an offer ends all matter. Compare the total cost, not only the headline rate, and see Loans, APR and car finance: comparing the real cost for how APR works on loans. Credit card interest explained: APR, minimums and payoff time shows what a single card costs at different payment levels. If you are building a buffer at the same time, How long to reach a savings goal helps you work out how much to put aside each month.
Glossary
- Snowball: clear the smallest balance first.
- Avalanche: clear the highest-APR debt first.
- Rolling: moving the payment released by a cleared debt onto the next one.
- Minimum payment: the least you must pay each month on a debt.
- Budget: the total you commit to debt payments each month.
When to get help
If your minimums are more than you can afford, a snowball or avalanche plan is not the right first step. Free, impartial debt advice is available from MoneyHelper and debt charities, and your lenders may be able to agree a reduced payment plan.
Frequently asked questions
Does avalanche always save more interest?
When the minimums cover the interest, it never costs more than snowball on the same budget, and the saving is larger when rates differ widely or the budget is tight. If rates are the same, the methods are the same.
What if my budget equals my minimums?
Then there is nothing extra to roll forward until a debt is cleared by its minimum payments alone. The order barely matters at first, and clearing will be slow.
Should I clear debt or save first?
That depends on the interest rate and your situation. Many people keep a small emergency cushion so that surprises do not go back onto a card. This is general information, so consider speaking to an adviser.
How many debts can the calculator handle?
Up to five, each with its own balance, APR and minimum. For more, combine similar small debts into one line for a close estimate.
Can I combine the methods?
Yes. Some people clear one tiny debt first for a quick win, then switch to avalanche. Run both through the calculator to see what the change costs.
Does the order matter if all my rates are the same?
No. If the rates are equal, every pound of interest costs the same, so the order makes no difference to the total.
What if one debt is a 0% balance?
Pay its minimum and send the extra to your highest-rate debt. Check when the 0% period ends, and bring that date into your plan.
Should I include my mortgage?
Usually not. A mortgage has a long term, usually a lower rate and secured borrowing, so most people leave it out of a snowball or avalanche plan.
How long should I keep the plan going?
Until the last debt is cleared. Update it whenever balances, rates or your budget change.