Debt Payoff Calculator
Add your debts, pick a strategy, and see exactly when you'll be debt-free. Snowball builds momentum with small wins; avalanche minimizes total interest. The tool runs in your browser — nothing you enter is uploaded.
Your debts
Add each debt with its current balance, interest rate (APR), and minimum payment. The calculator stays in your browser — nothing is uploaded.
Strategy
Results
Payoff order
- Add debts to see the payoff order.
Timeline
Show monthly payment schedule
Two strategies, one calculator
Both strategies pay every debt's minimum every month. The difference is where the leftover payment — your extra — goes.
- Avalanche targets the debt with the highest APR first. This minimizes total interest paid. Mathematically optimal.
- Snowball targets the debt with the smallest balance first. This pays your first debt off faster, which builds momentum. Statistically, more people who use snowball finish their plan.
The right answer is "the one you'll actually stick with." Try both, compare the debt-free dates, and pick. The interest difference between methods on a typical $20K mixed-debt scenario is usually a few hundred to a few thousand dollars over multiple years — meaningful, but smaller than the cost of giving up.
The "debt-free date" framing
The single most useful number this calculator gives you is the debt-free date. Not "total interest." Not "months remaining." The date.
Why: a date sticks in your head. "December 2028" is more motivating than "32 months" because you can see yourself there. You can put it on a calendar. You can plan around it. When you bump the extra payment from $100 to $200 and watch the date jump 8 months forward, the abstract math becomes a concrete decision: an extra hundred a month buys back almost a year of your life.
Read more in our blog post: The 'debt-free date' framing actually works.
How it works (the math)
Each month, the calculator:
-
Accrues monthly interest on every debt at
balance × APR ÷ 12. - Pays each debt's minimum (capped at the remaining balance for debts close to zero).
- Spends any remaining budget — minimums + your extra — on the target debt (smallest balance for snowball, highest APR for avalanche).
- If the target gets paid off mid-month, the leftover budget rolls to the next target. This is the "snowball" effect either method gets.
All math is done in cents internally to avoid floating-point drift
across hundreds of months. Read the full implementation in
sites/debt/src/lib/debt.ts on GitHub if you
want to verify.
Want the full schedule?
The on-page table shows the first 36 months for scannability. Click Download schedule CSV for the full month-by-month payoff schedule — open it in Excel, Google Sheets, or Numbers and slice however you like.
Related
- Personal finance hub — all our finance tools and guides
- Mortgage calculator — for mortgages specifically
- How to actually pay off debt — snowball, avalanche, hybrid
FAQ
Is anything I enter sent to a server?
No. The calculator runs entirely in your browser — open DevTools → Network and confirm. No data is uploaded, ever. Each value you type stays in memory in your tab.
What's the difference between snowball and avalanche?
Both throw your minimum payments at every debt. The difference is where the extra payment goes. Snowball targets the smallest balance — you pay off your first debt fastest and feel motivated. Avalanche targets the highest APR — you pay less interest in total but the first win takes longer. Most people who finish a debt payoff program use snowball; most spreadsheets that compute the optimum use avalanche.
How does the 'extra payment' interact with minimums?
Each month the calculator pays every debt's minimum first. The extra is added on top, then directed at one debt — the smallest (snowball) or highest-APR (avalanche). When that debt hits zero, its full payment (minimum + extra share) rolls into the next target debt. That rollover is the 'snowball' effect.
Why is my debt-free date so far away?
If you're paying close to the minimum, most of your payment is going to interest, not principal. A common pattern: a $5,000 credit card at 23.99% APR with a $100 minimum payment takes over 30 years to pay off — and you'll pay nearly $13,000 in interest. Try increasing the extra payment by even $50/month and watch the date jump forward.
What if my minimum payment doesn't cover monthly interest?
Then the debt grows every month and you'll never pay it off without extra payments. The calculator flags this as a warning. It's most common with low-minimum, high-APR balance-transfer cards after the promo period ends.
Does this work for student loans, mortgages, car loans?
Yes — any installment debt with a balance, APR, and minimum monthly payment fits. For mortgages specifically, the mortgage calculator has features (PITI, taxes, insurance) that this tool doesn't.