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Debt payoff calculator

List what you owe, add whatever extra you can pay each month, and compare the two classic ways to get out of debt.

DebtBalanceInterest % a yearMinimum a monthRemove

Avalanche

Highest interest rate first

Total interest

Snowball

Smallest balance first

Total interest

My money plan

Next step: Then give your next goal a date and a monthly amount: Savings goal calculator →

How to use the calculator

  1. List each debt in its own row: a name you'll recognise, the Balance you owe today, the Interest % a year from your statement or contract, and the Minimum a month you must pay.
  2. Use Add a debt for more rows (up to 8) and the ✕ button to remove one.
  3. Set Extra on top of the minimums to the amount you can add every month. Even a small extra makes a big difference, because it keeps rolling forward as debts disappear.
  4. Compare the Avalanche and Snowball boxes: when you'll be debt-free, the total interest and the order the debts are cleared in.
  5. Read the message under the boxes. It tells you how much avalanche saves, and warns you if a minimum payment doesn't even cover its interest.

What it's good for

  • Gives you a real debt-free date, which is the strongest motivation there is.
  • Shows the true cost of each method in money, so you can choose with your eyes open.
  • Reveals debts that would never be paid off at the minimum, before they cost you years.
  • Shows the rollover effect: every cleared debt makes the next one go faster.

Where it falls short

  • It assumes fixed rates, no new spending and no fees. Variable rates and late fees change the result.
  • It pays the extra on time every month. Real life has missed months; check again when things change.
  • It doesn't model consolidation loans, balance transfers or interest-free periods.
  • The cheapest method on paper only works if you stick to it.

How it's calculated

Formula. Each month: interest = balance × yearly rate ÷ 12 is added to every debt; then every minimum is paid; then the extra plus any freed-up minimums go to the target debt (avalanche: highest rate, snowball: smallest balance).

Worked example. A 3,000 card at 22%, an 8,000 car loan at 7% and a 600 store card at 15%, with 150 extra a month: avalanche is debt-free in 28 months with 1,352 interest; snowball in 28 months with 1,389.

Assumptions.

  • Rates stay fixed; no fees and no new spending.
  • Payments are made every month, after interest is added.

Formula checked 2026-10-23 and covered by automated tests. See the editorial policy and methodology.

Two methods, one rule

Both methods work the same way: pay the minimum on everything, and throw every extra euro at one target debt. When that debt is gone, its minimum payment joins the extra and rolls onto the next target. The payment you make each month stays the same; it just gets more powerful as debts disappear.

The only difference is which debt is the target.

  • Avalanche targets the highest interest rate. It's the mathematically cheapest way: you pay the least interest overall.
  • Snowball targets the smallest balance. It usually costs a bit more, but the first debt disappears quickly, and that early win keeps many people going.

Compare them above with your own numbers. If the difference in interest is small, pick the one you'll actually stick to. A plan you abandon after three months costs far more than either.

Before you start

  • Keep a small cushion first. About one month of essentials in an emergency fund, or the next surprise goes straight back on the card.
  • Stop adding new debt. Paying off a card while still using it is filling a bucket with a hole in it.
  • Find the extra in your budget. The household budget calculator shows where it can come from. Extra debt payments count as saving.
  • Check the real rate. Your statement or contract shows the annual rate. Store cards and overdrafts are often among the most expensive.

Why minimum payments are a trap

Minimum payments are set so the lender earns interest for as long as possible. If a minimum barely covers the monthly interest, the balance hardly moves; if it's below the interest, the debt grows even though you pay every month. The calculator warns you when a debt would never be paid off at its current minimum.

Questions

Should I invest or pay off debt first?
Paying off a debt is a guaranteed "return" equal to its interest rate. Very few investments reliably beat the rate on a credit card, so expensive debt usually comes first. Cheap, long debt like a mortgage is a different decision.
Does this include fees or rate changes?
No. It assumes fixed rates and no new charges. Variable rates, late fees and new spending all change the result.
What about consolidating my debts?
A consolidation loan can help if its total cost, including fees, is lower and you stop using the old cards. Compare the total you'd pay, not just the monthly payment.

Sources · last checked

Formula: see "How it's calculated" above; tested against the worked example shown there.

Last reviewed

Education, not advice. I'm not a financial adviser and I don't know your situation. These tools show the maths behind common rules of thumb; check important decisions with a qualified professional. Full disclaimer.