Debt Payoff Calculator

List every debt, add whatever you can pay above the minimums, and see exactly when you are free — with avalanche and snowball compared side by side.

DEBT FREE IN
2 yr 10 mo
TOTAL INTEREST
$3,825
TOTAL PAID
$25,525
Avalanche vs snowball on your numbers
StrategyTime to clearInterest paid
Avalanche (highest rate first)2 yr 10 mo$3,825
Snowball (smallest balance first)2 yr 11 mo$4,456

On your numbers, avalanche saves $631 in interest and clears 1 month sooner. Snowball clears small balances first, which some people find easier to stick with — the cost of that is the figure above.

Payoff order: Credit card → Personal loan → Car loan

About the Debt Payoff Calculator

Most debt advice tells you to pick a method and stick with it. That skips the only question that matters: what does each method actually cost you? This calculator runs your real balances through both the avalanche method and the snowball method at the same time, so you can see the exact difference in months and in interest before you commit. Enter every debt you carry, add whatever you can pay above the minimums, and the result is a debt-free date rather than a vague sense of progress. The maths is ordinary compound interest applied month by month; the value is in seeing both paths at once, and in the calculator refusing to give you a payoff date when the payment you have entered would never actually clear the balance.

Mathematical Formula & Logic

Each month is simulated in three steps, in this order. The order matters: interest is charged on the balance you carried into the month, before any payment lands. 1. Interest for the month i = B x (APR / 100) / 12 Where: - i = interest added this month - B = balance carried into the month - APR = annual percentage rate on that debt 2. Minimum payments Every debt except the target receives its minimum payment. 3. The target debt receives everything left Budget = sum of all minimums + your extra payment The target is chosen by strategy: - Avalanche: the debt with the highest APR - Snowball: the debt with the smallest remaining balance When a debt reaches zero, its minimum payment is not saved. It rolls into the money attacking the next target, which is why both methods accelerate as they go. This rolling effect is the part people underestimate most. A debt is only payable if the budget exceeds the interest accruing across all balances. If it does not, the balance grows every month no matter how long you pay, and this calculator tells you so instead of printing a date.

Step-by-Step Example

Three debts, a $200 monthly extra payment, and the avalanche method: Starting position - Credit card: $6,500 at 22.9% APR, $160 minimum - Car loan: $11,000 at 7.4% APR, $295 minimum - Personal loan: $4,200 at 12.5% APR, $120 minimum Step 1 - find the monthly budget Minimums: $160 + $295 + $120 = $575 Budget: $575 + $200 extra = $775 a month Step 2 - check the debt is payable at all Monthly interest at the start: - Card: 6,500 x 0.229 / 12 = $124.04 - Car: 11,000 x 0.074 / 12 = $67.83 - Personal: 4,200 x 0.125 / 12 = $43.75 Total: $235.62 a month in interest. The $775 budget clears that comfortably, so the balances will fall. Step 3 - pick the target Avalanche targets the highest rate, so the credit card at 22.9% is attacked first. It receives $775 minus the $295 and $120 minimums, which is $360, on top of nothing else. The car and personal loans receive only their minimums until the card is gone. Step 4 - the roll When the credit card clears, its $160 minimum does not disappear from the plan. It joins the extra, so the next target is attacked with $360 + $160 = $520 above the remaining minimum. This is why the last debts fall much faster than the first. Switch the strategy to snowball and the personal loan at $4,200 is targeted first instead, because it is the smallest balance. It clears sooner, which feels better, but the credit card keeps charging 22.9% in the meantime. The comparison table on this page shows exactly what that feeling costs in your case.

Reference Data & Values

rule nameformulaapplicability
Avalanche (highest APR first)Target = max(APR) among unpaid debtsMathematically optimal. Always pays the least total interest and is never slower than snowball. Best when the rate spread between your debts is wide, for example a 22% credit card sitting alongside a 6% car loan.
Snowball (smallest balance first)Target = min(balance) among unpaid debtsClears individual debts sooner, which some people find easier to sustain. Costs more interest than avalanche whenever the smallest debt is not also the dearest. The gap is small when your rates are similar and large when they are not.
Monthly interest on one debti = B x (APR / 100) / 12Charged on the balance carried into the month, before payment. This is why paying earlier in the month rarely helps but paying more always does.
Minimum viable paymentBudget > sum of all monthly interestBelow this threshold the total balance grows every month regardless of how long you pay. Any calculator that returns a payoff date below this line is misleading you.
The rolling payment effectExtra(next) = Extra(current) + minimum of the cleared debtApplies to both strategies. It is the reason payoff accelerates over time and why the final debt often clears far faster than the first.

Frequently Asked Questions

Avalanche always costs less interest, and it is never slower. Snowball clears individual debts sooner, which some people find easier to keep going with. The honest answer is that the best method is the one you actually stick to, which is why this calculator shows both side by side on your own numbers. If the difference is a few dollars, pick whichever motivates you. If it is several hundred, that is a real price for the psychological benefit and worth knowing before you choose.
It rolls into the amount attacking your next target. This calculator assumes you keep your total monthly payment constant rather than reducing it as debts clear, which is what both the avalanche and snowball methods prescribe. It is also the single biggest driver of how fast the plan finishes, and the reason the last debt usually clears much faster than the first.
Because there is not one. If your total monthly payment is less than the interest your balances accrue each month, the debt grows no matter how long you pay. Rather than printing a fictional date, the calculator tells you the minimum payment at which the balance actually starts to fall. Many calculators will happily return a number here; that number is wrong.
No. It assumes each APR stays fixed for the life of the debt and that no new fees or charges are added. Real credit cards often carry promotional rates that expire, annual fees, or variable rates tied to a benchmark. Treat the output as a planning estimate that shows the shape and relative cost of each strategy rather than a precise schedule. Re-run it whenever a rate changes.
This calculator does not answer that, and anyone giving you a blanket rule is oversimplifying. The comparison worth making is the interest rate on the debt against the return you would earn on the savings, after tax. A 22% credit card is very hard to beat with any investment; a 3% subsidised loan is a different conversation. Most guidance also recommends holding a small emergency fund before aggressive repayment, so that an unexpected bill does not push you straight back onto the card.
More than most people expect, because every dollar goes straight at the principal of your highest-priority debt and then compounds through the rolling effect. Change the extra payment field and watch both the debt-free date and the total interest move. Trying a few values is more informative than any rule of thumb, because the answer depends heavily on the rate spread between your debts.
No. The strategy decides the order of attack, not the order you type them in. Avalanche sorts by APR and snowball sorts by balance, both recalculated every month as balances change. You can enter them in any order that is convenient.
No. This is a calculator that performs arithmetic on the figures you provide, and the assumptions it makes are listed above. It does not know your income, your job security, your other obligations or your tax position. For decisions involving debt consolidation, settlement, or anything affecting your credit file, speak to a qualified adviser or a non-profit credit counselling service.