Methodology & sources
We’d rather show our work. Here’s exactly how the math works, what each example assumes, and where the facts come from.
How the calculators compute
- Card / minimum-payment payoff is simulated month by month: interest accrues on the balance, your payment is applied, repeat until paid off.
- Loan payments use the standard amortization formula for a fixed rate and term.
- Extra payments are added on top of the scheduled payment each month, which shortens the term and cuts total interest.
- Avalanche vs. snowball holds your total monthly budget constant and rolls freed-up minimums into the next target debt (highest APR first, or smallest balance first).
- Offer comparison adds any origination fee to the total of payments to show the true total cost.
All calculations run entirely in your browser. Results are estimates for education — they assume fixed rates, no new charges, and don’t account for every fee or grace-period detail. They are not a quote or a guarantee.
Where the facts come from
Figures and consumer-finance facts on this site are drawn from primary U.S. government and regulator sources, and are current as of June 2026 (rates and rules change — always confirm current details before acting):
- Consumer Financial Protection Bureau (CFPB) — minimum-payment math, credit inquiries, debt-relief guidance.
- Federal Trade Commission (FTC) — debt relief, the Telemarketing Sales Rule advance-fee ban, and scam warning signs.
- IRS Publication 4681 — tax treatment of canceled/forgiven debt and the insolvency exclusion.
This is general education, not financial, legal, or tax advice. See our disclosures.