About this planner
Last updated November 9, 2026
Which Debt First is a free tool for people with more than one debt who want to know where extra money does the most good. You enter your credit cards, car loans, personal loans, student loans and mortgages. The planner shows a payoff order, the date you could be debt-free, and how much interest you could avoid.
How the math works
Each month the planner adds interest to every balance. Interest is your APR divided by 12, times the balance. It then applies each required payment. All your extra money, plus the payments freed up by debts you have already paid off, goes to the first debt in your chosen order. It repeats until every balance reaches zero.
The comparison against minimum payments uses the same monthly steps with no extra money and no rolling of freed payments.
The three payoff methods
- Avalanche pays the highest interest rate first. It usually costs the least interest overall.
- Snowball pays the smallest balance first. You clear debts sooner, which some people find motivating. It can cost more interest.
- Cash flow pays first the debt whose monthly payment is large compared with its balance. It frees up monthly spending room fastest.
What the planner does not know
It cannot see fees, rates that change over time, promotional rates, skipped payments or new charges. It treats every payment as made on time. For mortgages, enter principal and interest only, not taxes and insurance. Treat the results as a guide, and check your lender's statement for exact payoff amounts.
Your numbers stay with you
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