Debt Snowball
Estimate payoff time when snowballing debts smallest balance first.
About Debt Snowball
Minimum payments are applied and extra money goes to the smallest balance, so the pool shrinks faster and the running time is estimated by the amortization formula. Quick wins on small balances keep motivation high, which for many people beats mathematically optimal but slower-feeling plans.
Formula
Debt Snowball
Payoff months = -ln(1 - rate x debt / payment) / monthly rate
- monthly rate
- APR divided by 12, used in the payment-to-interest ratio
Worked example
With the default values below, Debt Snowball returns Payoff Time of 19. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Total debtminimum 0
- 15,000
- Weighted APRaccepts 0–100 %
- 9 %
- Monthly paymentminimum 1
- 650
- Extra to first debtminimum 0
- 200
Results
- Payoff Time
- 19 months
- Total Interest
- $1,150
- Strategy
- Pay off the smallest balance first to build momentum
Step by step
- 1Values used
- 2Debt Snowball
- 3Payoff Time= 19 months
- 4Total Interest= 1,150
- 5Strategy= Pay off the smallest balance first to build momentum
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or fees or charges into account.
- Figures are rounded for display to whole numbers, 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
How is Debt Snowball calculated?
Payoff months = -ln(1 - rate x debt / payment) / monthly rate Minimum payments are applied and extra money goes to the smallest balance, so the pool shrinks faster and the running time is estimated by the amortization formula.
Why does Debt Snowball matter?
Quick wins on small balances keep motivation high, which for many people beats mathematically optimal but slower-feeling plans.
What values do I need to enter?
This calculator takes 4 inputs: Total debt, Weighted APR, Monthly payment, Extra to first debt. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.