How to use this calculator
- Add one row per debt: credit cards, car loans, personal loans, medical bills, student loans.
- For each one, enter the current balance, the interest rate (APR) and the minimum monthly payment. You’ll find all three on your latest statement.
- Enter the extra amount you can put toward debt each month, on top of all the minimums.
- Read the result. You’ll see your debt-free date, the total interest and the payoff order for both methods, side by side.
Results update as you type. Nothing you enter is sent anywhere: the math runs in your browser.
How the two methods work
Both methods start the same way. You keep paying the minimum on every debt, and you set a fixed monthly budget: all your minimums plus whatever extra you can afford. The difference is where that extra money goes.
- Debt avalanche: the extra goes to the debt with the highest interest rate. You attack the most expensive debt first.
- Debt snowball: the extra goes to the debt with the smallest balance. You knock out small debts quickly and build momentum.
When a debt is paid off, its minimum payment doesn’t disappear. Because your total budget stays the same, that freed-up money rolls into the next debt on the list. That rollover is what makes both methods accelerate over time.
The formula behind the numbers
The calculator runs a month-by-month simulation. Each month, for every debt:
Interest this month = Balance × APR ÷ 12
New balance = Balance + Interest − Payment
Extra for the target debt = Monthly budget − Minimum payments on all other debts
For example, a credit card with an $8,500 balance at 24.99% APR adds about $177.01 of interest in the first month ($8,500 × 0.2499 ÷ 12). If you only pay a $210 minimum, just $32.99 of it reduces the balance. That is why the order in which you put extra money to work matters.
Worked example
These are the numbers the calculator loads with. Four debts, $690 in combined minimums, plus $250 extra, for a monthly budget of $940.
| Debt | Balance | APR | Minimum |
|---|---|---|---|
| Credit card | $8,500 | 24.99% | $210 |
| Car loan | $12,000 | 6.9% | $290 |
| Medical bill | $900 | 0% | $50 |
| Personal loan | $4,200 | 11.5% | $140 |
| Avalanche | Snowball | |
|---|---|---|
| Debt-free in | 33 months | 33 months |
| Total interest | $4,497 | $5,296 |
| First debt paid off | Month 18 | Month 3 |
| Payoff order | Medical bill, credit card, personal loan, car loan | Medical bill, personal loan, credit card, car loan |
Avalanche saves $799 in interest because it clears the 24.99% credit card first. Snowball gets you a win in month 3 by wiping out the $900 medical bill, but the expensive card keeps charging interest longer. Both plans finish in the same month here, since the car loan is the last debt either way.
For comparison, paying only the minimums with no extra money would take 90 months and cost $12,879 in interest. Adding $250 a month and following either plan cuts more than four years off.
Which method should you pick?
On paper, the avalanche method always costs the same or less, because money goes to the most expensive debt first. In practice, the best plan is the one you stick with for years.
- Choose avalanche if you’re motivated by the numbers, or if one debt has a much higher rate than the rest, such as a credit card next to a low-rate car loan.
- Choose snowball if you’ve tried to pay down debt before and lost steam. Closing an account in the first few months is a real, visible result.
- Check the gap. If the calculator shows the two methods within a few dollars of each other, the choice is purely about motivation.
Ways to get debt-free sooner
- Raise the extra payment, even a little. Try $50 more in the calculator and watch the date move.
- Put windfalls to work. Tax refunds and bonuses applied to the target debt shorten the plan for every debt after it.
- Ask for a lower rate. A lower APR on your highest-rate card changes the avalanche order and the total interest.
- Stop adding new balances. The plan only works if the debts you’re paying down stay closed or unused.
Frequently asked questions
Which is better, the debt snowball or the debt avalanche?
The avalanche method costs the same or less in interest every time. The snowball method can be easier to stay with because small debts disappear sooner. Run your own numbers above: if the difference is small, pick the one that keeps you going.
How much more does the snowball method cost?
It depends on your debts. The gap grows when your smallest balances carry low rates and your biggest balances carry high rates. In the example above it is $799 over 33 months.
Should I include my mortgage?
Most people leave it out. A mortgage is usually large, long-term and low-rate, so it would sit last in either plan and stretch the timeline without changing the order of your other debts.
What if one of my debts has a 0% promotional rate?
Enter 0 for now, but note when the promotion ends. The calculator assumes each rate stays the same for the whole plan, so update the APR and run it again when the promo rate expires.
What happens to a minimum payment after a debt is paid off?
It rolls into the next debt in your plan. Your total monthly budget stays the same, so every payoff frees up more money for the debts that remain.
Is my information saved or shared?
No. The calculator runs entirely in your browser. If you use “Copy link to results”, your numbers are stored only in that link, so share it only with people you trust.
This calculator is for education and planning. It assumes fixed interest rates and on-time payments, and it isn’t financial advice. Your lender’s figures may differ slightly because of how they calculate daily interest.