🧗 Debt Payoff Planner

List your debts and see how the avalanche (highest interest rate first) and snowball (smallest balance first) strategies compare for payoff time and total interest paid.

What the month-by-month simulation does

Each debt is one line of Name, Balance, APR%, Min Payment. Every simulated month the planner charges interest, pays the minimums, then puts the whole extra pool on the first unpaid debt in the strategy's order:

interest = balance x (APR / 100 / 12)
pool     = extra + minimums freed by debts already cleared
avalanche: highest APR first   snowball: smallest balance first

The freed-minimum rollover does most of the work. On the built-in example - $4,500 at 22%, $12,000 at 6.5%, $18,000 at 5%, plus $200 extra - the card clears in month 17 and its $120 minimum joins the pool. Everything is gone in 51 months with $4,787 of interest; without the extra $200 it takes 75 months and $8,729.

The two strategies often agree

They diverge only when your smallest balance is not also your highest rate. In the default list the credit card is both, so avalanche and snowball return the identical 51 months. Put a $1,200 store card at 8% beside a $9,000 card at 22% and they split: $3,965 of interest against $4,229. Snowball's $263 premium buys a debt gone in month 6 rather than month 27.

If a minimum is smaller than that debt's monthly interest the balance grows and the run hits its 1,200-month ceiling. $5,000 at 24% accrues $100 in month one, so a $90 minimum never touches it.

Frequently asked questions

Is the avalanche or the snowball method better?

Avalanche always costs less interest, because it kills the most expensive money first. The gap is usually a few hundred dollars, so if clearing a small balance early is what keeps you paying, snowball is a fair trade.

How much difference does an extra $200 a month make?

On the sample $34,500 of debt it cuts payoff from 75 months to 51 and interest from $8,729 to $4,787 - $3,942 saved.

What counts as the minimum payment?

Whatever the lender demands: the fixed instalment on a loan, or the percentage-of-balance figure on a card. Enter a flat dollar amount - the planner holds it constant instead of shrinking it as a card balance falls, which makes it slightly conservative.