Debt / THE DECISION DESK
Debt Payoff Calculator
Compare the avalanche and snowball methods across your actual debts, and see how much the extra payment you can afford really buys you.
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2 yr 6 mo
Paying $810 a month using the avalanche method, clearing $21,200 of debt.
Avalanche — highest rate first
Snowball — smallest balance first
Difference
Total balance remaining
Both lines reach zero at almost the same time — the strategies differ far more in interest paid than in duration. Snowball's advantage is that individual debts disappear sooner, which is a motivation argument rather than a financial one.
View as table
| Months from today | Avalanche | Snowball |
|---|---|---|
| 0 mo | $21,200 | $21,200 |
| 1 mo | $20,597 | $20,597 |
| 2 mo | $19,986 | $19,987 |
| 3 mo | $19,367 | $19,371 |
| 4 mo | $18,739 | $18,747 |
| 5 mo | $18,104 | $18,116 |
| 6 mo | $17,459 | $17,476 |
| 7 mo | $16,806 | $16,828 |
| 8 mo | $16,144 | $16,170 |
| 9 mo | $15,473 | $15,504 |
| 10 mo | $14,792 | $14,828 |
| 11 mo | $14,103 | $14,143 |
| 1 yr | $13,403 | $13,449 |
| 1 yr 1 mo | $12,695 | $12,745 |
| 1 yr 2 mo | $11,976 | $12,031 |
| 1 yr 3 mo | $11,247 | $11,307 |
| 1 yr 4 mo | $10,508 | $10,573 |
| 1 yr 5 mo | $9,760 | $9,828 |
| 1 yr 6 mo | $9,003 | $9,073 |
| 1 yr 7 mo | $8,241 | $8,311 |
| 1 yr 8 mo | $7,475 | $7,546 |
| 1 yr 9 mo | $6,705 | $6,776 |
| 1 yr 10 mo | $5,931 | $6,002 |
| 1 yr 11 mo | $5,153 | $5,224 |
| 2 yr | $4,370 | $4,442 |
| 2 yr 1 mo | $3,583 | $3,656 |
| 2 yr 2 mo | $2,792 | $2,865 |
| 2 yr 3 mo | $1,997 | $2,070 |
| 2 yr 4 mo | $1,198 | $1,271 |
| 2 yr 5 mo | $394 | $468 |
| 2 yr 6 mo | $0 | $0 |
How this is calculated
This runs a month-by-month simulation rather than a formula, because the order debts are cleared in changes the answer and no closed form captures that.
Each month, in order:
1. interest accrues on every open balance at rate / 12
2. every minimum payment is made
3. the entire remaining budget goes to one target debt
4. any debt reaching zero releases its minimum into the budget
Step 4 is what makes either method accelerate. As debts are retired their minimums stop leaving your budget and roll into the payment on whatever is next — the payment against the remaining balance grows every time something is cleared, even though your total monthly outlay never changes.
The two strategies differ only in step 3. Avalanche picks the highest interest rate; Snowball picks the smallest balance. Everything else about the simulation is identical, which is why the comparison is a fair one.
If the budget is smaller than the interest accruing, the balance grows rather than shrinks. The simulation stops at 50 years and reports that the debt never clears instead of running forever.
Common questions
›Which is better, avalanche or snowball?
Avalanche always costs less. It targets the highest interest rate first, which is mathematically optimal, and no ordering can beat it on total interest. Snowball targets the smallest balance first, so it costs slightly more but retires individual debts sooner. The honest answer is that the gap is usually smaller than people expect — often a few hundred dollars across several years — so if an early win is what keeps you paying, snowball's psychological edge can be worth more than avalanche's arithmetic one.
›Why do both methods finish at almost the same time?
Because the total you pay each month is the same under either strategy. The order you clear debts in changes how much interest accrues along the way, but not how much money is going out the door. That is why the duration barely moves while the interest figure does. The thing that genuinely changes the timeline is the size of the extra payment.
›What counts as the minimum payment?
The contractual minimum your lender requires each month. For credit cards this is often a percentage of the balance with a floor, so it drops as the balance falls — this calculator holds it fixed, which is slightly conservative and means real payoff may be marginally faster than shown. For installment loans like an auto or student loan, the minimum is just the scheduled payment.
›Should I pay off debt or invest instead?
Compare the interest rate against what you would realistically earn after tax. Paying off a 23% credit card is a guaranteed 23% return, which almost nothing in the market reliably beats. At the other end, a 4% student loan is a much closer call against long-run market returns, and the answer depends on your tax situation and risk tolerance. The one thing worth doing before either is capturing any employer retirement match, which is an immediate return no debt rate matches.
›What does this not model?
Balance transfers and promotional rates, variable rates that move over time, fees and penalties, minimum payments that shrink as balances fall, and any new borrowing during the payoff period. It also assumes you never miss a payment. Treat the output as a comparison between strategies rather than a precise forecast of your payoff date.