Debt payoff calculator: avalanche vs snowball
Enter your debts and a monthly budget to see how long each payoff order takes, what each costs in interest, and every month in between.
- Calculated in your browser
- Formula and rounding
- Reviewed
Avalanche saves youExample
$275.50
18 months debt-free · avalanche interest $1,146.87 vs snowball $1,422.37
- Debt-free (avalanche)
- 18 months
- Debt-free (snowball)
- 18 months
- Total interest (avalanche)
- $1,146.87
- Total interest (snowball)
- $1,422.37
- Total repaid (avalanche)
- $8,646.87balances + interest
- Balances repaid$7,500.0087%
- Interest (avalanche)$1,146.8713%
Payoff order (avalanche)
highest APR first= Debt 1 → Debt 2
Months until debt-free
simulate monthly: interest, minimums, then the rest to the target debtbudget = 500debts = 2
= 18
Total interest
Σ round(balance × APR / 12)= 1146.87
- Avalanche (highest APR first)
- Snowball (smallest balance first)
Avalanche clears $7,500.00 of debt in 18 months with $1,146.87 of interest; snowball takes 18 months and $1,422.37. Avalanche costs $275.50 less in this scenario.
| Debt | APR | Start balance | Cleared | Interest paid |
|---|---|---|---|---|
| Debt 1 | 24.00% | $6,000.00 | Month 16 | $1,049.03 |
| Debt 2 | 6.00% | $1,500.00 | Month 18 | $97.84 |
| Debt | APR | Start balance | Cleared | Interest paid |
|---|---|---|---|---|
| Debt 2 | 6.00% | $1,500.00 | Month 5 | $20.30 |
| Debt 1 | 24.00% | $6,000.00 | Month 18 | $1,402.07 |
Assumptions
- Interest is charged monthly at APR ÷ 12 on the balance, rounded to the minor unit.
- The same total of $500.00 is paid every month; minimums first, the rest to the priority debt.
- Minimum payments are fixed amounts (card minimums that fall with the balance are not modelled). No new borrowing, fees or promotional rates.
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Estimates for general information only — not financial, credit or legal advice. Your actual figures depend on your lender’s or card issuer’s exact terms, fees, minimum-payment rules, interest calculation method and any changes they make. Check your statements and speak to a qualified adviser before making decisions. We assume the payments and minimums you enter stay fixed for the whole plan; real minimums and promotional rates can change. Disclaimer · Report an error
How to compare debt avalanche and debt snowball for your own debts
When you owe money on more than one card or loan and have a fixed amount to put towards them each month, the order you clear them in changes how much interest you pay. The debt avalanche targets the highest interest rate first. The debt snowball targets the smallest balance first. Both pay every minimum every month; they differ only in where the rest of the budget goes.
This debt payoff calculator runs both orders through the same debts and the same budget, month by month, and shows the months to debt-free, the interest each method costs and the difference between them. It calculates; it does not tell you which to pick. Our guide to debt avalanche vs snowball walks through the trade-offs in more depth.
- 1
List each debt
For every card or loan, enter the balance you owe, its APR and the minimum payment the lender asks for. Add a row for each debt; the figures on each statement are the ones to use.
- 2
Enter your monthly budget
Type the total you can put towards all debts each month, including the minimums. If it is below the sum of the minimums, the calculator tells you how far short it is instead of showing a plan.
- 3
Compare the two orders
The headline shows how much the cheaper method saves in interest. Below it you get months to debt-free and total interest for each method, the order each one pays your debts in, a balance chart and a month-by-month schedule you can download.
What this calculator does
- Avalanche (highest APR first) and snowball (smallest balance first) side by side
- Months to debt-free and total interest for each method
- The order each method pays your debts in, and the month each one is cleared
- Total balance chart for both methods
- Month-by-month schedule with CSV export
- Warnings when the budget is below the minimums or a minimum never clears a debt
- Any currency; nothing you type leaves your browser
Worked example: two debts, 500 a month
Debt A: 6,000 at 24% APR, minimum 150. Debt B: 1,500 at 6% APR, minimum 50. Budget: 500 a month.
In month 1, interest is added first: A gets 6,000 × 24% ÷ 12 = 120.00 and B gets 1,500 × 6% ÷ 12 = 7.50. The two minimums take 200 of the budget, leaving 300. The avalanche sends that 300 to A (the higher rate); the snowball sends it to B (the smaller balance). The same rules repeat every month until both balances are zero.
| Measure | Avalanche | Snowball |
|---|---|---|
| First debt cleared | A in month 16 | B in month 5 |
| Second debt cleared | B in month 18 | A in month 18 |
| Months to debt-free | 18 | 18 |
| Interest on debt A | 1,049.03 | 1,402.07 |
| Interest on debt B | 97.84 | 20.30 |
| Total interest | 1,146.87 | 1,422.37 |
| Total paid | 8,646.87 | 8,922.37 |
In this scenario the avalanche costs 275.50 less in interest. Both orders finish in month 18 because the budget and the total owed are the same; the saving shows up as a smaller final payment rather than a month saved. The snowball clears its first account eleven months sooner, which is the trade-off the two methods make. These are the figures the calculator shows when you first open it.
How it’s calculated
The calculator simulates one month at a time for each method and stops when every balance is zero. Each month, every open debt is charged interest, interest = round(balance × APR ÷ 12), rounded to the smallest unit of your currency and added to the balance. Every minimum is then paid, capped at the balance so a final payment can never overpay. Whatever is left of the budget goes to the target debt, and if that debt is cleared with money to spare, the remainder cascades to the next target in the same month.
Because the total budget is constant, the minimum of a cleared debt automatically joins the extra payment on the next one. That roll-over is what people call the snowball effect, and it applies to both orders. Total interest is the sum of every month’s interest charges, and total paid is the sum of every payment, which always equals the starting balances plus the interest.
The order is fixed at the start. Avalanche sorts by APR from highest to lowest; snowball sorts by balance from smallest to largest. Ties are broken the same way whatever order you typed the rows in, so the result does not depend on how you entered your debts. The difference shown in the headline is simply snowball interest − avalanche interest. The full rules, rounding and tests are on the methodology page.
Reading the results
The payoff order tables list your debts in the sequence each method targets them, with the month each one is cleared and the interest it accrued along the way. In the worked example, debt A collects 1,049.03 of interest under the avalanche but 1,402.07 under the snowball, because the snowball leaves the 24% balance almost untouched for its first five months. That single row usually explains most of the gap between the two totals.
The balance chart plots the total owed at the end of each month for both methods. The two lines start at the same point and end at zero; the area between them is the extra balance the snowball carries, which is where its extra interest comes from. The schedule lists the avalanche plan month by month, with interest charged, total paid and the balance left, and the CSV adds a column per debt.
Two warnings can appear. If your budget is below the sum of the minimum payments, the calculator names the shortfall instead of producing a plan, because both methods assume every minimum is paid. If a debt’s minimum is less than its first month’s interest, it is flagged as never repaid at the minimum: paying only that minimum would leave the balance growing. The credit card minimum payment calculator shows how long a single card takes at the minimum alone.
Related calculations
If you are weighing a single new loan against keeping your debts separate, the debt consolidation calculator prices the loan against the avalanche plan for the same debts, with any arrangement fee included. The credit card minimum payment calculator shows what happens to one card when only the issuer’s minimum is paid each month.
For the ideas behind the figures, read debt avalanche vs snowball for the trade-offs between saving the most interest and seeing quick wins, how credit card interest works for why daily interest and APR make a card balance grow, and credit card minimum payments explained for how issuers set the minimum and why it falls as the balance falls.
Good to know
- Minimum payments are treated as fixed amounts. Many card minimums are a percentage of the balance, so they fall over time; the calculator uses the figure you enter for the whole plan.
- Interest is charged once a month at APR ÷ 12. Card issuers often use daily balances and the exact timing of your payment, so their figures can differ by a small amount.
- Promotional 0% rates, balance-transfer fees, late fees and rate changes are not modelled. A debt on an introductory rate sits at the bottom of the avalanche order only while the offer lasts.
- The plan assumes no new borrowing on any of the debts. New spending on a card resets part of the calculation.
- Secured debts such as a mortgage or car loan carry different consequences from unsecured cards. The calculator orders by APR and balance only; it does not weigh that risk.
What happens to the numbers you type
Your numbers stay in your browser. DebtWren works out your results on your device. We don’t send the balances, rates or payments you type to our servers or store them. If you allow analytics, we record only broad ranges (for example “£2,000–£5,000 of debt”) to understand how the calculators are used. Like any website with ads, this page also loads advertising scripts; see our Privacy Policy.
The calculator is plain code running in this tab. It makes no network requests with your figures, and nothing is saved when you leave unless you choose to keep it. Read the privacy policy for how ads and analytics work on this site.
Related calculators and guides
- Debt avalanche vs debt snowball: how each method works and what it costsHighest rate first or smallest balance first, worked through month by month.
- How credit card interest works: APR, daily interest and grace periodsThe maths behind your card balance, and why the advertised rate is rarely the whole story.
Questions people ask
What is the difference between debt avalanche and debt snowball?
Both pay every minimum each month and send the rest of a fixed budget to one target debt. The avalanche targets the debt with the highest APR; the snowball targets the debt with the smallest balance. When one target is cleared, the next in the list takes over.
Which method saves more interest?
With a fixed budget and fixed rates, paying the highest rate first minimises total interest in almost every case. In the worked example on this page the avalanche costs 1,146.87 in interest against 1,422.37 for the snowball, a difference of 275.50. If you have two debts and the smaller one also carries the higher rate, both methods choose the same order and the results are identical. With more debts the two orders can still diverge after the first target, so the totals can differ even when both start with the same debt.
Why does the snowball still appeal to people if it costs more?
It clears the first account sooner. In the example, the snowball closes debt B in month 5 while the avalanche clears nothing until month 16. Fewer open accounts can mean fewer payments to manage and visible progress early on. The calculator shows both so you can weigh the saving against that.
What happens if my budget is less than my minimum payments?
The calculator does not produce a plan; it reports how far short the budget is of the total minimums. Both methods depend on every minimum being paid every month, and a plan that misses minimums would not be meaningful.
What does “never repaid at the minimum” mean?
The debt’s minimum payment is smaller than the interest added in its first month, so paying the minimum alone would leave the balance growing. For instance, 10,000 at 24% APR accrues 200.00 of interest in month 1, so a 150 minimum would not cover it. The balance only starts to fall once the total paid to that debt each month exceeds its interest, so a budget above the minimums is not enough on its own: in this example the budget would need to be above 200.00 a month (201 clears it in 268 months, 250 in 82). A budget that is above the minimums but still at or below the interest leaves the balance flat or growing, and the calculator reports the debt as not repaid within 100 years.
Why do both methods finish in the same month in the example?
The budget and the total owed are the same, so both plans run for a similar length. The 275.50 saved by the avalanche appears as a smaller final payment rather than a whole month cut from the plan. With larger balances or a wider spread of rates, the time difference grows.
Does the calculator use my card’s real minimum payment formula?
No. It uses the minimum amount you enter and keeps it fixed for the whole plan. Issuers usually set the minimum as a percentage of the balance plus interest, with a floor, so the real minimum falls over time. The minimum payment calculator models those rules for a single card.
Is anything I type sent anywhere?
No. The calculation runs in your browser and the balances, rates and payments you enter are not sent to our servers or stored. There is deliberately no share link on this tool, because debt figures are personal.
Sources and review
- Consumer Financial Protection Bureau — How to reduce your debt
- Consumer Financial Protection Bureau — What is a credit card interest rate? What does APR mean?
- Consumer Financial Protection Bureau — The minimum-payment box on a credit card statement
- Federal Reserve — Consumer Credit (G.19) statistical release
- Bank of England — Money and Credit statistical release
Estimates for general information only — not financial, credit or legal advice. Your actual figures depend on your lender’s or card issuer’s exact terms, fees, minimum-payment rules, interest calculation method and any changes they make. Check your statements and speak to a qualified adviser before making decisions. We assume the payments and minimums you enter stay fixed for the whole plan; real minimums and promotional rates can change.
Page reviewed by the DebtWren team · Methodology · Changelog · Report an error