Debt Payoff Calculator (Snowball & Avalanche)
List your debts, add anything extra you can pay each month, and see the payoff order, your debt-free month and the interest you will pay — with the snowball and avalanche methods compared side by side.
Your plan
Your debts
| Debt | Balance | APR % | Min payment | Actions |
|---|---|---|---|---|
— to clear every debt
Total interest — · Total paid —
—
Amounts use the same currency as the balances above.
—
Month-by-month schedule
| Month | Interest | Paid | Balance left |
|---|
What this calculator does
It takes a list of debts — each with a balance, an annual interest rate and a minimum monthly payment — plus any extra you can put towards them, and simulates the months until everything is paid off. The result is the order each debt is cleared, the month you become debt-free, the total interest and the total paid. The same numbers are run through both the debt snowball and the debt avalanche so the two methods can be compared directly.
How the payoff is calculated
Every month each open debt is charged interest once on its opening balance at the monthly
periodic rate, APR ÷ 100 ÷ 12. The minimum payments are then made, and whatever
is left of the month's budget — your extra amount plus the minimum payments freed up by debts
already cleared — is aimed at the target debt, then the next, until it is used up. Because a
cleared debt no longer spends its minimum, that money rolls onto the next debt automatically:
this is the “snowball” effect, and it is why an extra payment compounds.
Debt snowball vs debt avalanche
| Method | Target first | Best if |
|---|---|---|
| Snowball | Smallest balance | You need quick wins to stay motivated. |
| Avalanche | Highest interest rate | You want the lowest total interest. |
The avalanche almost always costs less interest; the snowball usually clears the first debt sooner. The difference depends on how spread out your balances and rates are.
Example
A single £/$1,200 balance at 0% with a $100 monthly payment clears in 12 months with no interest. Add a 22.9% credit card and the same total payment, and the order you pay in starts to matter — which is what the snowball/avalanche comparison shows.
This is an estimate for planning, not financial, tax or legal advice, and not a lender statement. Interest is modelled as monthly compounding and real statements may differ. If you are struggling with debt, contact a non-profit debt advice service in your country.
Frequently asked questions
What is the difference between the debt snowball and the debt avalanche?
Both pay the minimum on every debt and throw all spare cash at one target. The snowball targets the smallest balance first, so you clear debts — and feel progress — sooner. The avalanche targets the highest interest rate first, so you pay the least interest overall. The calculator runs both on the same numbers, so you can see the difference rather than guess.
Does paying extra actually help?
Yes, and the effect is larger than most people expect because the extra payment goes straight to the principal of the target debt, while the minimum payments you free up are rolled onto the next one. Enter an extra monthly amount to see both the time and the interest it saves.
How is the interest worked out?
Each month the interest is charged once on the opening balance, using the monthly periodic rate (APR ÷ 100 ÷ 12), then the payments are applied. This is the standard credit-card style of monthly compounding; it is an estimate, not a lender statement.
Why does it say my debts never get paid off?
If the total you pay each month is less than the interest being charged, the balances never fall. That usually means one of the minimum payments is too low for its rate. Increase the monthly payment or the extra amount and recalculate.
Is this financial advice?
No. It is a calculator that shows the arithmetic of a repayment plan. It does not know your full finances and does not recommend products. Speak to a qualified adviser before making a decision.
Is my data sent anywhere?
No. Everything runs in your browser; the balances, rates and payments you type never leave your device and are not stored.
Go deeper
Longer explanations of the problems this tool solves:
Sources
- U.S. Federal Trade Commission, Debt Collection FAQs — your rights under the Fair Debt Collection Practices Act, including when collectors may contact you and how long negative information stays on a credit report. consumer.ftc.gov
- Consumer Financial Protection Bureau, consumer tools and debt resources — consumerfinance.gov/consumer-tools.
Everything runs in your browser — nothing you type is uploaded.