Debt Payoff Calculator
Formulate an accelerated debt repayment strategy, compare interest-minimizing Avalanche vs balance-eliminating Snowball methods, and identify your exact debt-free date.
Debt Portfolio
3 LiabilitiesRepayment Rollout Cascade
Step-by-step sequential allocation under the Avalanche Model
Mathematical Mechanics: Amortization
The monthly compounding finance charge on each liability is calculated via:
The Avalanche method is mathematically optimal because every extra dollar goes to the balance charging the highest rate, which minimizes the total interest accruing across all your debts. Any dollar allocated to a 22.4% APR balance earns a guaranteed return of 22.4%.
Avalanche vs Snowball Trade-Off
Debt Avalanche
Maximizes mathematical efficiency. Saves the most in interest charges and usually reaches debt freedom soonest, but the first payoff can take a while.
Debt Snowball
Prioritizes behavioral momentum. Eliminates small accounts early, generating quick psychological wins that reduce friction and the number of bills you juggle.
How this calculator works
Each month, every debt accrues interest at its APR ÷ 12 and receives at least its minimum payment. Your extra amount goes to the target debt — the highest APR for avalanche, the smallest balance for snowball. When a debt is paid off, its minimum rolls into the next target, so your total monthly outlay stays the same until you're debt free. The "minimums only" scenario keeps that same total but adds no extra.
Why the payment amount matters so much
On high-interest debt like credit cards, a payment close to the minimum can take years to clear and cost more in interest than the original balance. Increasing the monthly payment even modestly often cuts both the payoff time and total interest dramatically.
A worked example
A $5,000 balance at 19.99% APR with a $150/month payment takes about 50 months (4 years, 2 months) to pay off, with roughly $2,357 in total interest — meaning you'd pay about $7,357 total for the original $5,000. Bump the payment to $250/month instead, and payoff time drops to about 25 months with around $1,132 in interest — roughly halving both the timeline and the total interest.
For a multi-debt walkthrough with real numbers, see avalanche vs snowball, worked through. Once your obligations drop, check how it moves your debt-to-income ratio.
Frequently asked questions
What if my payment doesn't cover the interest?
If your monthly payment is lower than the interest accruing each month, the balance will never be paid off — you'll need to increase the payment above that threshold. The calculator flags any debt whose minimum doesn't cover its interest.
Should I pay off high-interest debt before investing?
As a general rule, paying off debt with a higher interest rate than your expected investment return tends to provide a better guaranteed outcome, though individual circumstances vary.
Which is better: avalanche or snowball payoff method?
Avalanche (highest interest rate first) saves more money mathematically. Snowball (smallest balance first) can be more motivating since it produces quick wins, even at a slightly higher total cost — the best method is the one you'll actually stick with.
Should I pay off debt or save simultaneously?
Most financial guidance suggests keeping a small emergency fund while aggressively paying down high-interest debt, then shifting focus to savings once high-interest balances are cleared.
How much does avalanche actually save over snowball, in real numbers?
On $14,700 across three debts (24.99%, 19.99%, and 11.5% APR) with $300/month extra, avalanche saves $178 in interest over 25 months — but takes until month 12 to eliminate its first debt, versus month 7 for snowball. See the full worked example.
Is a 0% balance transfer worth the fee?
On a $6,700 balance at 23% APR paid off over 18 months, a 0% intro card with a 3% transfer fee ($201) saves about $1,084 versus staying put. The transfer stops being worth it once your original APR drops below roughly 3.8%.
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