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Debt avalanche calculator UK
A debt avalanche calculator shows the order to clear your debts, highest interest rate first, and how much interest that saves. Free for UK credit cards, loans and overdrafts, with no sign-up.
Your details
Add your debts and payment assumptions, then compare snowball with avalanche.
Results
Compare your payoff strategies
Run the plan to compare payoff timing, total interest, and the month-by-month path for each strategy.
Your payoff comparison will appear here
Add your debts and run the calculator.
How it works
How the debt avalanche works
Clear the highest rate first
Pay the minimum on everything, then put any extra money towards the debt with the highest interest rate, whatever its balance.
Roll each payment forward
When a debt is cleared, add its payment to the debt with the next highest rate. Each pound goes where it saves the most interest.
Guide
The debt avalanche method, explained for UK debts
What the avalanche is, how to use the calculator, a worked example in pounds, and when a different approach makes more sense.
What is the debt avalanche method?
The debt avalanche is a way to pay off several debts by clearing the highest interest rate first, whatever the balance. You keep paying the minimum on everything else and put any spare money towards your most expensive debt. When it is cleared, its payment moves to the debt with the next highest rate.
Because your extra money always goes where interest is building fastest, the avalanche usually costs the least in total interest of any payoff order. The trade-off is that your first debt can take longer to clear if your most expensive debt is also a large one.
How to use the debt avalanche calculator
You need four things for each debt, all of which are on your latest statement or in your banking app:
- Balance: what you owe today.
- APR: the yearly interest rate. This decides the order, so check it carefully. For an overdraft, use its yearly overdraft rate.
- Minimum payment: the least you have to pay each month. For an overdraft, enter what you plan to pay off.
- Extra monthly payment: anything you can pay on top of all your minimums. This is the biggest lever on your debt-free date.
Run the plan to see which debt to clear first, the month each debt is paid off, your total interest and your estimated debt-free date. You can switch to the snowball order at any time to compare. Prefer a spreadsheet? The free debt snowball spreadsheet has an avalanche option too.
Worked example: clearing £10,000 with the debt avalanche
Here is a typical mix of UK debts: two cheaper loans and two expensive revolving debts. The minimum payments add up to £320 a month, and this household can find an extra £150, so £470 goes towards debt every month.
| Debt | Balance | APR | Minimum | Cleared in |
|---|---|---|---|---|
| Overdraft | £1,300 | 39.9% | £40 | Month 8 |
| Credit card | £4,200 | 29.9% | £125 | Month 24 |
| Car finance | £1,500 | 9.9% | £60 | Month 25 |
| Personal loan | £3,000 | 7.9% | £95 | Month 27 |
- Paying only the £320 of minimums takes 52 months and costs about £6,420 in interest.
- Adding £150 a month with the avalanche clears everything in 27 months, with about £2,418 of interest.
- That is 25 months sooner and roughly £4,002 less interest than paying the minimums.
The overdraft goes first, in month 8. Its payment then moves to the credit card at 29.9%, which is cleared in month 24. The snowball order would move on to the smaller car finance instead and leave the credit card until last. It finishes in 28 months with about £2,885 of interest: £467 more and 1 month longer.
The gap grows when your most expensive debt is also your biggest, and shrinks when your rates are close together. Try your own numbers in the calculator above and switch between the two orders.
Debt avalanche vs debt snowball
| Debt avalanche | Debt snowball | |
|---|---|---|
| Pays first | Highest interest rate | Smallest balance |
| Total interest | The least | Usually a little more |
| First debt cleared | Can take longer | Usually sooner |
| Best for | Paying the lowest total cost | Staying motivated with quick wins |
Both methods use the same total payment; they only change the order. Read more about the debt snowball calculator, or run both on your own debts with the snowball vs avalanche calculator.
When the avalanche is hard to stick with
If your most expensive debt is also a large one, it can be many months before anything is fully paid off, and that can feel like no progress. A few things help:
- Watch your total balance and monthly interest fall, not just the number of debts left. The calculator's Summary table shows both.
- If a tiny balance is weighing on you, clearing it first costs little and removes a payment. Then go back to the avalanche order.
- If the saving for your debts is only a few pounds, the snowball's quicker wins may be worth more to you.
What the debt avalanche doesn't cover
The avalanche is for non-priority, unsecured debts: credit cards, store cards, overdrafts, personal loans, car finance and buy now pay later. Keep two other kinds of debt out of it.
- Priority debts, such as rent or mortgage arrears, Council Tax, gas and electricity, court fines, TV Licence, child maintenance and tax owed to HMRC. Missing these can lead to eviction, disconnection or enforcement, so they always come first. MoneyHelper explains how to prioritise your debts.
- Secured debts, such as your mortgage, which run on their own schedule. The mortgage overpayment calculator is a better fit for those.
If you can't afford your minimum payments
The avalanche only works if you have money left after your minimums. If you are already missing payments, start with free debt advice instead. It is free, confidential and won't judge you.
- Breathing Space gives you up to 60 days' legal protection from most creditor action in England and Wales while you get advice, with most interest and charges frozen. A debt adviser can apply for you. Read about Breathing Space on GOV.UK.
- A debt management plan can lower your monthly payments to what you can afford. Free providers such as StepChange don't charge for setting one up.
How we calculate
Each month the calculator adds interest to every balance at its APR divided by 12, takes off your payments, and repeats until every balance reaches zero. In avalanche order:
- Every debt gets its minimum payment, which stays the same each month until that debt is cleared.
- Your extra payment goes to the debt with the highest APR. If two rates are equal, the smaller balance goes first.
- When a debt is cleared, its minimum payment rolls onto the next debt in the order.
It assumes your rates stay the same, you make every payment and you don't borrow more. Promotional rates, fees and changes in your circumstances will move the real date, so treat it as an estimate and rerun it when something changes.
Educational information only. Zero Debt is not regulated by the Financial Conduct Authority (FCA) and this calculator is not financial advice. For advice about your situation, speak to a free debt advice service.
Sources
Debt avalanche calculator FAQs
Is this debt avalanche calculator free?
Yes. The calculator is free and works in your browser without an account. Enter your debts and you get your payoff order, total interest and estimated debt-free date straight away.
How much will the debt avalanche save me?
It depends on how different your interest rates are and where your biggest balances sit. The saving is largest when your most expensive debt is also one of your biggest, and small when your rates are similar.
In the worked example on this page the avalanche costs £467 less interest than the snowball. Enter your own debts in the calculator above and switch between Avalanche and Snowball to see your figure.
Is the debt avalanche or the debt snowball better?
The avalanche, which pays the highest interest rate first, usually costs the least in interest. The snowball, which pays the smallest balance first, usually clears your first debt sooner, which many people find easier to stick with.
If the saving is small for your debts, the method you will keep going with matters more. See the debt snowball calculator or compare both side by side in the snowball vs avalanche calculator.
What if two of my debts have the same interest rate?
The calculator pays the smaller balance first. Clearing it sooner frees up its minimum payment for the next debt, at no extra cost in interest.
How do I add an overdraft?
Enter your overdrawn amount as the balance and your overdraft rate as the APR. Arranged overdrafts are charged at a single yearly rate, often around 35% to 40%, so an overdraft often sits at the top of an avalanche.
Overdrafts have no required monthly payment, so enter the amount you plan to pay off each month as the minimum payment.
How do 0% balance transfers and promotional rates fit in?
Enter the rate you pay now. A 0% balance falls to the bottom of the avalanche, so your extra money goes to debts that are charging interest.
When a promotional rate ends, the balance jumps to a higher rate and may need to move up the order, so rerun your plan before the end date. The balance transfer calculator shows what you need to pay each month to clear a 0% balance in time.
How do FCA minimum payment rules affect the avalanche?
Under FCA rules (CONC 6.7.5R), a credit or store card minimum payment must at least cover that month's interest, fees and charges plus 1% of the balance. As your balance falls, so does the minimum on your statement.
To keep the avalanche working, keep paying the same amount rather than dropping to the lower minimum. This calculator assumes you do that: each minimum payment stays fixed until the debt is cleared.
What is persistent credit card debt?
You are in persistent debt if, over 18 months, you have paid more in interest, fees and charges than you have paid off the balance. Your card provider must contact you at 18 and 27 months. At 36 months they must offer you a way to repay faster, and they can suspend the card if you cannot.
The avalanche targets your most expensive card first, which is usually the one most at risk of persistent debt.