What the Debt Avalanche Calculator does
This debt avalanche calculator plans your repayments so that every spare amount goes to the debt with the highest interest rate first, while minimums are paid on everything else. It shows the payoff month of each debt, the total interest and the debt-free date, and compares all of it side by side with the snowball order for exactly the same monthly budget.
Mathematically, the avalanche is the cheapest way to repay a set of debts with fixed rates and payments. The comparison tells you how much cheaper in your own case - sometimes hundreds, sometimes nothing - so the decision between the two methods is based on your numbers.
How to use it
- Add each debt's balance, APR and minimum monthly payment, or paste them as a list.
- Enter the extra you can pay each month on top of the minimums, and your first payment month.
- Read the debt-free date and the interest saved compared with the snowball; the payoff table also shows the month each debt would clear under the snowball.
- Open the schedule to see what to pay on each debt every month and download it for your records.
Reading the results
The order column ranks debts from highest to lowest APR. That is the order in which the extra money is aimed.
Interest saved versus snowball is the difference in total interest for the same budget. When the highest-rate debt is also the smallest, both methods give the same plan.
The avalanche can take longer to clear the first debt, because the most expensive debt is often a large one. The chart shows total balance falling under both orders.
Worked example: two debts, highest rate first
Debt A is 300 at 24% APR and debt B is 100 at 0%, each with a 50 minimum, and there is 100 extra a month - a budget of 200. The avalanche targets A because its rate is higher.
Month 1: A accrues 6.00 to 306; after both minimums A is 256 and B 50; the extra 100 goes to A, leaving 156. Month 2: A accrues 3.12 to 159.12; B's last 50 clears it, and the other 150 brings A down to 9.12. Month 3: A accrues 0.18 and 9.30 clears it.
Total interest is 6.00 + 3.12 + 0.18 = 9.30, against 10.32 for the snowball order on the same debts and budget - a 1.02 saving. On larger balances and wider rate gaps the difference grows: the page's second example saves about 600.
Formulas and scoring rules
- Monthly interest
interest = balance x APR / 12- Budget
all minimums + extra payment, held constant; freed minimums roll to the next debt- Order
highest APR first; equal APRs go to the smaller balance- Interest saved
saved = snowball total interest - avalanche total interestBoth plans use the same debts, budget and start month. Money shown to 2 decimals.
When the avalanche makes the biggest difference
The saving is largest when a big balance carries a high rate and smaller balances carry low ones - a typical pattern for a large credit card balance alongside small 0% or low-rate finance plans. In the second example on this page, a 29.9% card beside two low-rate debts, the avalanche saves about 600 of interest and a month of payments.
When your rates are similar, or the smallest debt also has the highest rate, the orders converge and the method matters little. Then choose the one you find easier to follow.
Limitations: what the result does not prove
- It assumes fixed rates, no new spending and on-time payments. 0% offers that end, balance transfer fees and penalty rates are not included.
- Interest is modelled monthly at APR / 12; lenders using daily interest will differ slightly.
- Minimum payments are held constant at what you enter.
- It is a calculation, not financial or debt advice. Priority debts such as rent, mortgage and utilities may need paying before any of this.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
- US CFPB - paying down debt - checked 19 Sep 2026
Frequently asked questions
What is the debt avalanche method?
You pay the minimum on every debt and send all extra money to the one with the highest interest rate. When it is paid off, its payment moves to the next highest rate. Because the most expensive debt shrinks fastest, less interest builds up overall.
How much does the avalanche save compared with the snowball?
It depends entirely on your balances and rates. The calculator runs both orders on the same budget and reports the difference. In the four-debt example it is about 217; with a large high-rate card beside small low-rate debts it is about 600.
Should I use APR or the interest rate on my statement?
Use the annual percentage rate the lender charges on the balance. If a debt has different rates for purchases and cash advances, enter them as separate debts with their own balances so the order is right.
Does the avalanche ever cost more than the snowball?
Not with fixed rates and payments as modelled here: it gives the lowest or equal interest. It can take longer to clear the first debt, and if motivation drops and payments stop, the saving on paper does not happen - which is why the snowball is still popular.
What if two debts have the same rate?
The calculator targets the smaller balance first among debts with equal rates. That costs nothing extra in interest and clears one debt sooner.
Where do I find my minimum payments and APRs?
They are printed on each monthly statement and in your online account. Use the current balance, not the original loan amount. For a loan with a fixed monthly instalment, enter the instalment as the minimum.
Last reviewed by the A2Z.Tools team against the sources listed above.
