Debt Payoff Calculator
Compare the snowball and avalanche methods across all your debts at once - see which clears first, what each costs in interest, and when you are free.
Debt Payoff Calculator
Your debts
Must cover every minimum: $325 combined.
Debt free in
2 years 2 months
Total interest
$1,723
Total repaid
$15,523
First cleared
Store card
vs other strategy
$0 less
In interest
Avalanche targets the highest rate first and always costs less — here, $0 less in interest. Snowball targets the smallest balance first, clearing Store card earlier. That is not irrational: a Harvard Business School study found people were more likely to stick with the snowball, and a plan you abandon saves nothing at all.
Payoff order
| Debt | Rate | Cleared | Interest |
|---|---|---|---|
| 1.Store card | 26.99% | month 4 | $61 |
| 2.Credit card | 22.99% | month 16 | $799 |
| 3.Car loan | 6.9% | month 26 | $863 |
Every debt keeps receiving its minimum throughout. Only the surplus above the minimums goes to the target debt — and when one clears, its minimum joins that surplus, which is why the last debts fall much faster than the first.
If you switched strategy
Avalanche (current)
2 years 2 months
$1,723 interest
Snowball
2 years 2 months
$1,723 interest
The link carries the values you entered, so whoever opens it sees the same result. Nothing is stored on our side — the numbers travel in the link itself.
How the debt payoff calculation works
With one debt, paying it off is arithmetic. With several and a fixed monthly budget, the order you clear them in changes both the total interest and the date you finish — and averaging the rates into a single loan gets both wrong.
How the payoff actually works
Every month, the same three things happen:
- Interest accrues on each balance at its own rate.
- Every debt receives its minimum payment.
- Everything left over goes entirely to one target debt.
When the target clears, its minimum joins the pool attacking the next one. That rollover is why payoff accelerates: the first debt is slow, and the last one falls in weeks. Both methods below use this structure — they differ only in which debt is the target.
Avalanche: highest rate first
Target the highest interest rate, regardless of balance. This is mathematically optimal — it always costs the least interest and never finishes later. If the arithmetic is all you care about, this is the answer.
Snowball: smallest balance first
Target the smallest balance, regardless of rate. It costs more in interest, sometimes substantially, but it clears an entire debt sooner. That matters more than it sounds: a 2015 Harvard Business School study found people were more likely to stay with the snowball to completion, and a plan you abandon halfway saves nothing at all.
The calculator runs both and shows the real cost of the difference, so it is a decision you make with a number rather than a slogan.
One thing that surprises people
A very small debt clears first under either method. Avalanche directs only the surplus above the minimums, and the minimums keep paying every debt regardless. So a £300 store card with a £30 minimum disappears in ten months whether you targeted it or not. The two methods only genuinely diverge when the smaller debt is large enough that the surplus decides its fate.
When the budget will not stretch
If your combined minimums exceed what you can pay, no ordering helps — the balances grow whatever you do. The calculator says this outright rather than producing a forty-year schedule that implies the plan works. That situation calls for a non-profit credit counselling service, a hardship programme with the lender, or a consolidation loan at a lower rate. All three are ordinary and none of them are a last resort.
Consolidation and balance transfers
A 0% balance transfer card genuinely helps if you clear the balance inside the promotional window. Model it by entering the debt at 0% for the promotional period — but be honest about the transfer fee, typically 3% to 5%, and about what happens on the day the rate reverts.
Disclaimer: This calculator provides estimates for informational purposes only and is not financial advice. Your actual rate, taxes, fees, and payment will vary - confirm figures with a licensed lender or financial professional.
Frequently asked questions
Which is better, the debt snowball or the debt avalanche?
Avalanche always costs less in interest and never takes longer, because it attacks the most expensive debt first. Snowball clears a whole debt sooner, which research suggests makes people more likely to finish. If the gap in interest is small - and with similar rates it often is - take the snowball. If it is thousands, take the avalanche. This calculator shows the exact difference for your debts rather than leaving it as a matter of opinion.
Should I pay off debt or build savings first?
Most guidance suggests a small emergency fund first - often one month of expenses - then aggressive debt repayment, then a fuller fund. The reason is practical rather than mathematical: without any buffer, the next unexpected bill goes back onto the credit card and undoes the progress. Above roughly 8% interest, paying debt down beats almost any guaranteed return you could earn on savings.
What if I cannot afford the minimum payments?
Then the ordering question is moot and the balances will grow whatever you do. Contact the lenders before missing a payment - most have hardship programmes that reduce or pause payments, and they are far more willing to arrange one in advance than after a default. A non-profit credit counselling service can negotiate a debt management plan on your behalf, usually at reduced or zero interest.
Does a balance transfer card actually help?
It helps if you clear the balance within the 0% window and account for the transfer fee, typically 3% to 5% of the amount moved. It hurts if you treat the freed-up credit limit as spending room, or if the balance is still there when the promotional rate ends and reverts to 20% or more. Model it honestly: enter the fee as part of the balance, and assume you pay it off before the window closes.
Why does paying more each month save so much more than it seems?
Because every extra pound goes entirely to principal and stops accruing interest immediately, and because clearing one debt sooner releases its minimum to attack the next one earlier. The effect compounds through the whole plan. Increasing the budget by 10% typically cuts the payoff time by considerably more than 10%. Try it above - the change is usually larger than people expect.
Should I include my mortgage or student loans?
Usually not in the same plan. Mortgages and subsidised student loans carry much lower rates and often tax advantages, so putting them in the pool diverts money from debt costing three times as much. Include anything above roughly 8% to 10%. Keep the low-rate debts on their normal schedule and revisit them once the expensive ones are gone.
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