Debt Repayment Calculator
Add your debts, choose a payoff strategy, and see exactly how long it will take and how much interest you’ll pay to become debt-free.
Your Debts
| Debt Name | Balance | APR | Min. Payment |
|---|
Payoff Order & Breakdown
Avalanche vs Snowball Comparison
Debt Repayment Calculator: Avalanche vs Snowball
Our Debt Repayment Calculator helps you build a payoff plan for multiple debts at once — credit cards, store cards, personal loans and car finance. Add each debt’s balance, interest rate and minimum payment, choose between the Debt Avalanche or Debt Snowball method, and see exactly how long it will take to become debt-free and how much interest you’ll pay along the way.
How the Debt Avalanche and Debt Snowball Methods Work
Both methods use the same total monthly payment — your combined minimum payments plus any extra you can afford. The difference is which debt receives the extra money first, while every other debt still gets at least its minimum payment.
- Debt Avalanche: extra payments go to the debt with the highest interest rate first, then the next highest, and so on. This minimises the total interest you pay over the life of the plan.
- Debt Snowball: extra payments go to the debt with the smallest balance first, regardless of interest rate. This can clear smaller individual debts sooner, creating quicker milestones and a sense of progress, though it may cost slightly more in total interest.
In both methods, once a debt is cleared, its minimum payment is added to the pool used for the next target debt — so your planned monthly payment stays broadly consistent throughout the plan, with more and more of it going toward the debt still remaining. The final payment on any individual debt can be smaller than scheduled, since you only ever pay off the remaining balance rather than overpaying once it reaches zero.
How to Use the Debt Repayment Calculator
- List your debts using the table — name, current balance, APR (interest rate) and minimum monthly payment for each. Use “Add Another Debt” for more rows.
- Enter any extra monthly payment you can put toward debt on top of your minimums.
- Choose a strategy — Debt Avalanche or Debt Snowball.
- Click Calculate Payoff Plan to see your time to debt-free, total interest, payoff order for each debt, and a side-by-side comparison of both strategies.
Worked Example
Consider four debts: a £4,000 credit card at 24.9% APR, a £900 store card at 18.9% APR, an £8,000 car loan at 7.9% APR, and a £2,000 personal loan at 12.9% APR, with minimum payments of £100, £30, £180 and £60 respectively, plus an extra £200 a month.
| Strategy | Time to Debt-Free | Total Interest Paid |
|---|---|---|
| Debt Avalanche | 2 years 7 months | £2,381.53 |
| Debt Snowball | 2 years 7 months | £2,674.75 |
In this example, the Avalanche method (paying off the 24.9% credit card first, then the 18.9% store card) saves around £293 in interest compared to the Snowball method, which clears the smaller £900 store card first even though it carries a lower rate than the credit card. The Snowball approach does clear its first debt in just 5 months, versus 16 months for the first debt cleared under Avalanche — which is the trade-off between motivation and minimising cost.
Which Method Should You Choose?
- Choose Avalanche if: you’re focused on minimising total interest and can stay motivated without quick wins.
- Choose Snowball if: you’ve struggled to stick with a debt payoff plan before and benefit from the psychological boost of clearing smaller debts fully, faster.
- Either way: making any extra payment beyond the minimum, on any debt, will reduce your total interest and payoff time compared to paying minimums only.
Tips to Pay Off Debt Faster
- Always pay at least the minimum on every debt to avoid late fees and credit score damage — this calculator assumes minimums are paid on all debts throughout.
- Direct any spare income, bonuses or tax refunds toward your extra monthly payment to shorten your payoff timeline.
- Consider a balance transfer card or debt consolidation loan for high-interest credit card debt, which can lower your effective APR — re-run the calculator with the new rate to compare.
- Avoid taking on new debt while working through your payoff plan, as this increases the minimum payments the calculator assumes stay fixed.
- Review your interest rates periodically — promotional 0% periods on credit cards will expire, changing which debt should be prioritised under Avalanche.
Frequently Asked Questions
What is the difference between debt avalanche and debt snowball?
Debt avalanche directs extra payments to the debt with the highest interest rate first, minimising total interest paid. Debt snowball directs extra payments to the smallest balance first, clearing individual debts faster to build momentum, which can cost slightly more in total interest.
Which method saves more money, avalanche or snowball?
Debt avalanche typically results in less total interest paid because it targets the highest interest rate first. The exact saving depends on your specific balances and rates — in our worked example above, avalanche saved around £293 compared to snowball on the same debts and extra payment.
Does paying off debt in a different order change how long it takes?
Not necessarily by much. Your planned total monthly payment (minimums plus extra) stays broadly consistent regardless of strategy, so the overall time to become debt-free is often very similar between methods — though the final payment on any given debt can be lower than scheduled once its remaining balance is smaller than the payment due. What differs most between strategies is which debt is cleared first and how much total interest accrues along the way.
What happens to a debt’s minimum payment once it’s paid off?
Once a debt is fully repaid, this calculator rolls its minimum payment into the extra payment pool for your next targeted debt, so your planned total monthly outgoing towards debt stays broadly consistent throughout your payoff plan. The final payment on any debt can still be lower than scheduled once its remaining balance is smaller than the payment due.
What if my minimum payments don’t cover the interest?
If your combined minimum payments and extra payment are less than the interest accruing each month, your total balance will grow rather than shrink. The calculator will warn you if this is the case — you’ll need to increase your payments to make progress.
Does this calculator include mortgage debt?
You can include a mortgage as one of your debts, but this calculator uses a simple interest-accrual model designed for credit cards, personal loans and car finance. For a dedicated mortgage repayment or overpayment projection, use our Mortgage Calculator or Mortgage Overpayment Calculator instead.
Can I switch strategy partway through?
Yes — you can re-run the calculator at any time with your updated balances to see the remaining payoff plan under either strategy. Many people start with snowball for early motivation and switch to avalanche once they have momentum, though sticking with one method usually gives the most predictable results.
Are the interest rates in this calculator APR or a simple annual rate?
This calculator uses a simplified monthly interest model: your entered annual rate divided by 12, applied to the remaining balance each month. This is a reasonable approximation for many credit cards and personal loans, but it will not exactly match every lender’s calculation — some lenders charge interest daily rather than monthly, and your actual cost can also be affected by promotional 0% periods, balance transfer fees, annual fees, or other account-specific terms. Check your statement or lender for the precise method used on your account.