Debt-Free Date
Nov 2029
39 months
£25,500.00
£2,673.03
£2,737.31
54 months faster
The snowball only rolls if the extra payment is actually there
Set up your budget in iBudget, give the snowball its own line, and see each debt fall off the list.
Free plan available · No bank connection required · Export or delete your data any time · Cancel any time
- 1
Credit Card
Paid off in month 10
Jun 2027
- 2
Car Loan
Paid off in month 22
Jun 2028
- 3
Student Loan
Paid off in month 39
Nov 2029
Monthly Payment: £725.00(£525.00 minimums + £200.00 extra)
Minimum Payments Only
- Time to payoff:
- 93 months
- Total interest:
- £5,410.34
- Monthly payment:
- £525.00
Snowball Method
- Time to payoff:
- 39 months
- Total interest:
- £2,673.03
- Monthly payment:
- £725.00
How the debt snowball calculator works
The snowball is an ordering rule, not a payment formula. Here is the arithmetic this page actually runs, month by month.
The formula
bₘ = bₘ₋₁ × (1 + r ÷ 12) − minₘ − snowballₘ- bₘ
- One debt's balance at the end of month m. The calculator runs this line once per month for every debt you enter, in parallel, until every balance is zero.
- r
- That debt's annual interest rate as a decimal — 24.5% typed into the box is r = 0.245 — divided by twelve to get a simple monthly rate of 2.0417%. Interest is added to the balance before any payment is applied.
- minₘ
- The contractual minimum you entered for that debt, held constant for the whole run and capped at the remaining balance so the final payment is never an overpayment.
- snowballₘ
- Everything above the minimums, applied to one debt at a time in snowball order: your extra payment, plus the minimums freed by debts already cleared, plus any part of this month's minimums that exceeded the balance it was paying.
- order
- Debts are sorted by starting balance, smallest first, once before month one. The order does not change as balances change.
Balances below half a cent count as cleared, and totals are rounded to the nearest cent only at the very end. The simulation stops after 600 months, or earlier if a month ends with a total balance no smaller than the one it began with — in which case the tool reports that these payments never clear the balance rather than inventing a date.
Adopting the snowball changes nothing about the cost of borrowing. Each debt still accrues interest at its own rate on its own balance. What changes is the destination of the money you hold above the minimums, and the snowball rule sends all of it to the smallest balance rather than the most expensive one.
Each month the calculator does four things in order. It charges a month of interest to every outstanding debt. It works out the redirectable pot — your extra payment plus the minimums of debts already cleared. It pays the minimum on every debt still standing, rolling any unused fraction of a minimum into that pot rather than discarding it. Then it empties the pot into the debts in snowball order, taking each to zero before moving on.
The consequence is an invariant worth internalising: your total outlay never changes while any debt is still standing. In the worked example below it is $655 every month from month one to month 27, and only the final month is smaller, because there is just $17.75 left to pay. Clearing a debt does not reduce what you pay, it enlarges what hits the next one — which is exactly why the method has the name it does.
The comparison drawn here is against a deliberately narrow baseline. In the minimum-only column there is no extra payment and no redirection: each debt gets its fixed minimum, and when one clears, that money simply stops. The gap between the two columns is therefore the value of two separate decisions — finding the extra payment, and refusing to let a freed-up payment disappear back into your spending.
A worked example
Three debts, one extra payment, run end to end. US dollars, but the arithmetic is identical in any currency.
$15,300 across three debts, $200 a month extra
Worked example- Personal loan — smallest, so the first target
- $900 at 9.9%, $40 minimum
- Credit card
- $5,400 at 24.5%, $135 minimum
- Car loan
- $9,000 at 7.4%, $280 minimum
- Total outlay, every month
- $40 + $135 + $280 + $200 = $655
- Month 1 interest on the target
- $900 × 9.9% ÷ 12 = $7.43
- Month 1, minimum applied
- $907.43 − $40 = $867.43
- Month 1, snowball applied
- $867.43 − $200 = $667.43
- Personal loan cleared
- Month 4
- Snowball from month 5
- $200 extra + $40 freed minimum = $240
- Credit card cleared
- Month 21, snowball now $375
Paying only the three fixed minimums with no extra takes 84 months and costs $7,092.84, so this plan saves $4,690.09 and finishes 56 months sooner. Ordering the same debts by interest rate instead, the avalanche clears the credit card first and finishes in 27 months for $2,253.99 — meaning the snowball costs $148.76 and one extra month, under 1% of the total repaid. That is the honest price of taking the visible win first.
How to read your result
The debt-free date is the headline, but it is not the number that should change your behaviour.
Look at the gap between the two comparison columns before you look at the date. That gap is what your extra payment buys, and it responds sharply to small changes. Add another $25 or £25 and re-run it: every unit removed from an expensive balance stops accruing interest for the entire remaining run.
Then sanity-check the rates you entered, because guessing them low is the most common way to get a comfortable, wrong answer. On a store card or an arranged overdraft the true rate sits well above the headline averages below — the CFPB put average US store card APRs at 31.3% in 2024 against 25.2% on general purpose cards, and the average UK arranged overdraft rate was 34.55% in June 2026.
A result worth acting on usually looks like this: a first debt clearing within three to six months, total interest that is a small fraction of the balances themselves, and a monthly outlay you could sustain in a bad month. If your first payoff is more than a year out, the snowball is not buying you its main benefit and you may as well take the avalanche's cheaper schedule. For scale, US consumers were charged $160 billion in credit card interest in 2024, up from $105 billion two years earlier, and around half of all US card accounts carry a balance from month to month — whatever your number is, it is not an unusual problem.
22.15%
US average card rate on balances actually charged interest
2026 Q2, preliminary. The 'all accounts' rate, which averages in people who pay in full, was 20.94%.
24.69%
UK average rate on credit card lending bearing interest
June 2026, 20.94 points above base rate. The average arranged overdraft was 34.55%.
$5,300
US average monthly card balance per cardholder
2024. Averaged across all cardholders including those who clear in full, so a revolver's balance is higher — about $8,700 for prime-scored cardholders.
£2,751
UK credit card debt per household
May 2026. Again averaged across every household, including the majority carrying no balance, so a revolving household owes considerably more.
15%
US cardholders paying only the minimum
2024, the highest share since at least 2015, and 20% on store cards. This is the group the minimum-only column models.
27 yr 10 mo
Time to clear an average UK card balance on minimums alone
Modelled on £2,751 with a minimum of interest plus 1% of the balance. Freezing the payment at the first month's £79 clears it in 4 years 11 months.
What this calculator does not account for
Every payoff model simplifies. These are the specific simplifications this one makes.
Minimum payments are frozen, but real ones shrink
You enter one minimum per debt and the calculator reuses it every month. Real card minimums recalculate as interest plus a percentage of the balance, so they fall as the balance falls — which is what stretches minimum-only repayment across decades. The comparison column is therefore kinder to the minimum-only path than reality, so your true saving is probably larger than shown.
Interest is a simple monthly rate, not daily compounding
The rate you type is divided by twelve and applied to the whole outstanding balance once a month, before any payment lands: a 24.5% APR becomes 2.0417% a month. Real cards compound daily on an average daily balance, so the true figure differs by a small amount over a long run — typically a few pounds or dollars, not a few hundred.
No fees, grace periods or rate changes
Every balance accrues interest from month one at one fixed rate: no interest-free window on purchases, no separate cash advance rate, no 0% period that expires, no penalty APR after a missed payment. Fees are invisible too — annual, late, over-limit, balance transfer and early repayment charges. On a transfer the fee can be a meaningful share of the interest you are avoiding.
You never spend on these accounts again
The model assumes each balance only ever falls. One purchase mid-plan and the real schedule slips behind the projected one immediately. This is the assumption that breaks most often, and the reason a small cash buffer usually belongs in front of an aggressive extra payment.
Instalment loans are modelled as revolving balances
A car or student loan is treated as a balance with a rate and a payment, not a contractual amortisation schedule. That is close enough to compare payoff orders, but it ignores fixed terms, settlement figures and restrictions on overpaying. Income-contingent student loans with forgiveness rules behave nothing like this and should be left out.
The payoff order is fixed before month one
Debts are sorted by starting balance once, and the order never changes. If a larger debt falls below a smaller one partway through, a stricter reading of the rule would switch targets and this calculator will not. The difference is usually small, but the schedule you see is the order set on day one.
Everything is nominal, and nothing is compared against saving
Interest totals are in today's money, with no inflation adjustment and no tax treatment. The tool makes no attempt to compare paying down debt against investing the same money, building an emergency fund, or capturing an employer pension match — above roughly 15-20% interest that comparison is rarely close, but below it, it can be.
Affordability is assumed, not tested
The result assumes you make every minimum plus the extra payment, every month, for the full run without a single miss. It knows nothing about your income, your other bills, or whether a debt is already in arrears. The debt-free date is simply today plus the number of months the simulation took.
None of this makes the comparison useless: the ranking of the two strategies is robust to all of it, because the same assumptions apply to both columns. It does mean the absolute figures are an estimate, and that anyone already struggling should treat a payoff schedule as the wrong tool. New clients of the UK charity StepChange owed an average of £16,874 in unsecured debt in 2025, median £9,999 — at those levels advice is worth more than arithmetic.
Frequently asked questions
The awkward ones included.
What is the debt snowball method?
The debt snowball is an ordering rule, not a payment formula. You pay the contractual minimum on every debt, then send every spare pound or dollar to the smallest balance until it is gone. When it clears, the payment it was absorbing joins the attack on the next-smallest debt, so the amount hitting one balance grows each time something falls off the list.
Why pay the smallest balance first instead of the highest interest rate?
On arithmetic alone you should not: ordering by interest rate is never worse and is usually cheaper, because you retire expensive money first. The case for the snowball is behavioural — clearing a whole debt early is visible proof the plan works, and a plan you keep beats a cheaper plan you abandon in month five. The calculator can price the difference; it cannot model whether you will stick with it.
How much does the snowball actually cost me compared with the avalanche?
Usually less than people expect, and sometimes nothing. In the worked example above the snowball costs $148.76 more and finishes one month later on $15,300 of debt — under 1% of the total repaid. If your smallest balance also carries your highest rate, the two methods produce an identical schedule. Run the same debts through the avalanche calculator and compare the interest figures.
What counts as the extra payment?
Anything you can pay every month, on top of every minimum, without fail. It is a single figure rather than one per debt because the method depends on that money always landing on one target. If your surplus varies, enter what you would still manage in a bad month, so the result is a floor rather than a fantasy.
Should I include my mortgage in the snowball?
Usually not. The snowball is built for consumer debt — cards, store cards, overdrafts, car finance, personal loans — where rates are high and balances are small enough to clear. A mortgage is secured, cheap by comparison, and long enough that including it drowns the schedule. It is also modelled poorly here, since every debt is treated as a revolving balance rather than a contractual amortisation.
What about a 0% balance transfer card?
Enter it at 0% and no interest accrues, which is right for the promotional window and wrong the day it ends. Nothing in the tool knows about promotional expiry, so a 0% card looks free forever. If the balance will not clear before the deal ends, run it twice — once at 0%, once at the go-to rate — and plan against the worse one. The transfer fee is not modelled either.
What minimum payment should I enter when my card recalculates it every month?
Enter today's minimum. The calculator holds it constant, whereas a real card minimum is typically interest plus a percentage of the balance and so falls as you pay down. That makes the minimum-only comparison column kinder than reality: The Money Charity models a UK minimum as interest plus 1% of the balance and finds an average household card balance would take 27 years and 10 months to clear that way, against 4 years and 11 months if you froze the payment at the first month's figure.
Should I build an emergency fund before I start the snowball?
A small buffer first is the usual advice, because without one the next unexpected bill goes straight back onto a card and undoes months of progress. Bankrate's 2026 survey found 29% of Americans have more credit card debt than emergency savings, against 44% with more savings than card debt. This calculator assumes you never add to a balance again — exactly the assumption a thin buffer breaks.
What does it mean when the calculator says the debt never clears?
It means a month ended with a total balance no smaller than the one it started with: interest is accruing faster than your payments retire it. The simulation stops there — or after 600 months, whichever comes first — and reports N/A rather than inventing a date. No repayment order fixes that, and it is the point at which free debt advice or a formal arrangement beats a calculator.
Does paying debts off in this order hurt my credit score?
Clearing balances generally helps, because it lowers the share of your available credit in use. Two effects run the other way: closing a card after you clear it cuts your total available credit, and paying off an instalment loan slightly narrows your credit mix. Neither justifies keeping an expensive balance alive, and none of it is modelled here — this tool computes money, not scores.
Does this handle arrears, defaults or a debt management plan?
No. Priority debts — rent, mortgage arrears, council tax, child support, tax bills — carry consequences unrelated to interest rates and belong at the front of the queue whatever their balance. Debts already in default, in an arrangement, or with interest frozen do not behave like this model. In that position, free advice from a charity is worth more than any payoff schedule.
Where to go next
What to read once you have a number, and the other calculators that pair with this one.
Read next
- Debt Snowball vs Avalanche: Which Payoff Method Is Right for You?A full worked amortisation of the same debts under both orders, and the cases where snowball is still the right call.
- How to Stop Living Paycheck to Paycheck: A 30-Day PlanWhere the extra payment actually comes from when there is no obvious surplus to redirect.
- How Much Emergency Fund Do I Need? Work Out Your NumberHow big a buffer needs to be before an aggressive debt plan survives contact with a broken boiler.
- Dealing with Debt in the UK: Your Complete Guide to Debt SolutionsWhat to do when the numbers do not work: debt management plans, DROs, IVAs and where free advice comes from.
Debt Avalanche Calculator
Attack the highest interest rate first to pay the least overall.
Open calculatorTrack your debt payoff journey
Sign up for iBudget to track your debt payoff progress, set milestones, and celebrate every win on your journey to financial freedom.