Undebt.it

Undebt.it covers more ground than most payoff calculators. Beyond the standard snowball (smallest balance first) and avalanche (highest interest rate first) methods, it offers six additional strategies, including ordering debts by highest monthly payment or letting you build a fully custom order based on whatever matters most to you, a card you want closed for a specific reason, say, regardless of its balance or rate. You can start using it without creating an account, plugging in balances and rates to see a payoff timeline immediately.

The core tool is free, with an optional low-cost paid tier that removes ads and adds a few extras like extra payment tracking across multiple scenarios. It integrates with YNAB for people who already track their budget there and want their debt payoff plan to pull from the same numbers. Having been online for more than a decade, it’s a stable, no-frills option for anyone who wants more flexibility than a basic snowball-versus-avalanche calculator without paying for a dedicated app.