How this debt payoff calculator works
Enter each debt's balance, its interest rate (APR) and its minimum monthly payment. Then add the extra amount you can put toward debt every month. The calculator runs two plans month by month:
- Debt snowball: pay the minimum on everything, and send all extra money to the smallest balance first.
- Debt avalanche: pay the minimum on everything, and send all extra money to the highest interest rate first.
In both plans your total monthly payment stays the same. When a debt is paid off, its minimum payment "rolls over" to the next debt in line. That rollover is what makes both methods so much faster than paying minimums. Each month, interest is added at APR ÷ 12, then payments are applied. Your payment dates start from the month you pick.
Snowball or avalanche: which should you choose?
The avalanche method always costs the same or less interest, because the most expensive debt shrinks first. If your debts have very different interest rates (for example a 29% store card and a 5% student loan), the savings can be hundreds or thousands of dollars.
The snowball method pays off your first debt sooner. That quick win matters. Many people quit a payoff plan because progress feels slow, and closing a whole account in the first few months keeps you going. If the interest difference shown above is small, the snowball may be the better choice for you.
A practical middle path: start with the avalanche. If a tiny balance is sitting there, clear it first for the motivation, then switch.
Example
The example debts total $25,400 with $590 in minimum payments. With $200 extra per month ($790 in total), both methods clear the 29.9% store card first (it is both the smallest balance and the highest rate), and both finish in about 38 months. After that they split. The snowball attacks the $3,800 car loan next because it's smaller, and the avalanche attacks the 24.9% credit card because it's more expensive. The avalanche saves about $180 in interest. Paying only the minimums would take almost 10 years and cost over $12,000 in interest. Change the extra amount and see what happens: even $50 more per month usually cuts several months off.
Tips for paying off debt on an irregular income
- Set the extra payment from a slow month, not a good one. Commit to an amount you can pay every month. Send bonus money from great months as one-off lump sums.
- Keep a small cash buffer first. If one bad month pushes you back onto a credit card, the plan stalls. A starter buffer protects your progress. Our pay-yourself-a-salary calculator helps you size it.
- Ask for a lower rate. A lower APR on your biggest balance helps both methods. Balance transfers can help too, but watch the transfer fees and the date the promo rate ends.
- Don't forget taxes. Freelancers who use tax money to pay down debt often end up with a new debt in April. Set tax aside first with the tax set-aside calculator.
Frequently asked questions
Is the debt avalanche always cheaper than the snowball?
Yes, or at worst the same. Putting extra money on the highest-rate debt reduces interest fastest. The two methods only cost the same when the smallest debt also has the highest rate, or when all rates are equal.
What if my minimum payment is less than the monthly interest?
Then that debt never shrinks on minimums alone. The calculator will say a plan is not paid off within 50 years. Increase the extra payment or that debt's minimum until the payment beats the monthly interest (balance × APR ÷ 12).
Does the calculator include new charges or fees?
No. It assumes you stop adding new debt and that rates stay the same. Variable-rate cards, annual fees and late fees will change the real result, so treat the dates as estimates and re-run the numbers every few months.
Should I pay off debt or build savings first?
Most people do best with a small emergency buffer first, then aggressive debt payoff, then a bigger savings goal. Without a buffer, one surprise bill goes back on the card.
Is my data saved or sent anywhere?
Your numbers are stored only in your own browser (local storage) so they're still there next time. Nothing is sent to a server.
These calculators are for education and planning. Results are estimates based on the numbers you enter and are not financial, tax or legal advice. See our disclaimer.