Debt Snowball vs Avalanche Calculator
Two methods dominate advice on paying off several debts at once. The debt avalanche pays minimums on everything and puts every spare dollar on the debt with the highest interest rate, which mathematically minimises total interest. The debt snowball does the same but targets the smallest balance first, so you wipe out debts quickly and build momentum. This calculator runs both on your own debts — balances, APRs and minimum payments — and compares months to debt-free, total interest and the order in which each debt disappears, along with the baseline of paying minimums only. The difference is often smaller than people expect, and the “better” method is the one you will actually stick to.
How to use the debt snowball vs avalanche calculator
- List each debt on its own line: name, balance, APR (%), and minimum monthly payment, separated by “|”.
- Enter the extra amount you can add each month on top of the combined minimums.
- Compare avalanche and snowball: time to debt-free, total interest and the interest saved.
- Check the payoff-order table, then pick the method you can sustain — and automate the payments.
Formula
Each month: interest = balance × APR ÷ 12 is added to every balance; minimum payments are made on all debts; then all remaining money — your extra plus the minimums freed up by paid-off debts — goes to the target debt. Avalanche targets the highest APR first; snowball targets the smallest balance first. The total monthly budget stays constant (sum of minimums + extra), which is what gives both methods their “rolling” effect.
Worked examples
Four debts
With a $4,000 card at 24.99%, a $9,000 loan at 7.5%, an $800 store card at 29.99% and a $12,000 car loan at 5%, and $150 extra a month: avalanche finishes in 3 y 0 m · interest $3,331.36, snowball in 3 y 0 m · interest $3,331.36, and paying minimums only takes 4 y 10 m · interest $5,975.83. Avalanche saves $0.00 over snowball.
Why the gap can be small
In this example the smallest balance (the store card) also has the highest rate, so both methods attack it first. When the smallest balance has a low rate, the methods diverge more and avalanche saves more.
The power of extra
Without any extra payment both methods are identical to paying minimums only. Adding even $50 a month starts the rollover effect: try changing the extra amount to see the months and interest change.
Practice problems
Try these yourself first, then check your answer. The answers come from the calculator above.
- Two debts: $2,500 at 21% (min $75) and $6,000 at 6% (min $120), with $100 extra a month. Which method is faster and how much interest does avalanche save?
Show answer
Debt-free sooner with: Both finish together · Avalanche (highest interest first): 2 y 9 m · interest $1,028.41 · Snowball (smallest balance first): 2 y 9 m · interest $1,028.41
Common mistakes to avoid
- Skipping minimum payments on any debt. Late fees and credit damage outweigh any method’s savings.
- Choosing a method for pure maths when you need motivation — or the reverse. A plan you quit is worth nothing.
- Forgetting new spending. Paying down cards while adding to them cancels the effect.
- Ignoring 0% promotional rates and deadlines; list them with their real APR after the promotion ends.
- Not rerunning the numbers when balances, rates or income change.
Frequently asked questions
What is the difference between snowball and avalanche?
Avalanche pays the highest-interest debt first to minimise interest; snowball pays the smallest balance first for quick wins and motivation.
Which method saves more money?
Avalanche saves the most interest by design, though the difference is often modest. Snowball can win in practice if it keeps you motivated.
How does the calculator handle extra payments?
Your extra amount, plus the minimum payments freed up as each debt is cleared, is rolled onto the next target debt.
What if my minimum does not cover the interest?
The calculator tells you the debt would never be repaid and asks for a higher payment or an extra amount.
Should I pay off debt or invest?
It depends on your interest rates and goals. High-interest debt such as credit cards usually beats typical investment returns, but speak to a qualified adviser about your situation.
Is this financial advice?
No. It is an educational comparison based on the numbers you enter.
By Thomas M, Registered Investment Adviser (South Carolina), who launched his own financial advisory firm in 2010. Last reviewed September 26, 2026. Found a mistake? Tell us; see our editorial policy.