Debt Payoff Calculator
Compare avalanche and snowball strategies across all your debts and see which wins.
About Debt Payoff Calculator
The avalanche strategy minimises total interest paid by targeting the highest-rate debt first. The snowball strategy maximises psychological wins by clearing the smallest balance first — you see debts disappear faster, which many people find motivating. Mathematically, avalanche always wins on total cost; the snowball's only edge is behavioural. This calculator runs month-by-month simulations for both so you can see the exact trade-off for your specific debts.
Formulas
Monthly interest per debt
Monthly interest = Balance × (APR / 12)
- B_j
- Balance of debt j
- APR_j
- Annual rate of debt j as decimal
Avalanche priority
Extra budget → debt with highest APR
Snowball priority
Extra budget → debt with smallest remaining balance
Worked example
With the default values below, Debt Payoff Calculator returns Avalanche — Payoff Time of 45. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Debts (one per line)
- 5000,22.99,100,Credit Card A 3000,18.0,60,Credit Card B 8000,7.5,150,Car Loan
- Extra Monthly Budgetaccepts 0–100,000 $
- 200 $
Results
- Avalanche — Payoff Time
- 45 months
- Avalanche — Total Interest
- $3,637.95
- Snowball — Payoff Time
- 46 months
- Snowball — Total Interest
- $4,098.75
- Interest Saved by AvalancheHow much more the snowball strategy costs in interest.
- $460.80
- Months Saved by Avalanche
- 1
Step by step
- 1Debts entered= 3 debts, $16,000.00 total
- 2Monthly budget= $510.00
- 3Avalanche result= 45 months, $3,637.95 interestPayoff order: Credit Card A → Credit Card B → Car Loan
- 4Snowball result= 46 months, $4,098.75 interestPayoff order: Credit Card B → Credit Card A → Car Loan
- 5Avalanche advantage= Saves $460.80 and 1 month(s)
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Which strategy should I choose?
Avalanche minimises total interest — if your debts have very different APRs, the difference can be thousands of dollars. Snowball gives you quicker wins: paying off your smallest debt in a few months keeps you motivated. Research suggests people who use the snowball approach are more likely to stick with it and actually become debt-free.
How do I enter my debts?
One line per debt: balance, APR%, minimum monthly payment, and an optional name, separated by commas. For example: 4500, 23.99, 90, Chase Sapphire. You can enter up to 5 debts.
What does 'extra monthly budget' mean?
After paying the minimums on all debts, any money left over is your extra budget. This is the amount you can direct strategically — toward the highest-APR or smallest-balance debt depending on your strategy.
Why is the payoff time the same for both strategies?
If all your debts have the same APR, or if your balances happen to already be ordered from smallest to highest APR, both strategies produce the same result. The avalanche advantage grows with APR spread between debts.