Data changelog
Guidelines get revised, limits get inflation-adjusted, and papers get superseded. When any figure behind a calculator on this site changes, it gets an entry here with the date. The formulas and their sources are listed on the methodology page.
Full formula registry for the payoff wing: fixed-payment amortization (CFPB 1943), snowball and avalanche ordering (CFPB debt-reduction guidance), balance-transfer fee math (CFPB 53), the deferred-interest retroactive charge (CFPB 40), and credit utilization (CFPB 318).
formulas.json
Initial data packs: monthly-interest and minimum-payment formulas (CFPB), issuer minimum-payment conventions (CFPB December 2025 market report), and reference card APRs (Federal Reserve G.19, May 2026).
formulas.json · min-payment-conventions.json · card-apr.json