These are the primary sources the calculators and guides rely on. Every link below was checked on September 30, 2026. For how the math itself works, see the methodology page.
Regulations
- Regulation Z, Appendix M1: Repayment Disclosures (CFPB). The method card issuers use for the payoff estimates on your statement. We cite it because it allows a monthly periodic rate (APR divided by 12) and treats a payoff estimate as accurate within 2 months.
- Regulation Z, §1026.7(b)(12): Repayment disclosures (CFPB). What a card statement must show: the minimum payment warning, how long paying only the minimum would take and cost, and, when that takes more than three years, the payment that clears the balance in 36 months.
- Credit CARD Act of 2009, Public Law 111-24 (govinfo). The law, enacted May 22, 2009, whose Section 201 added those payoff disclosures. We use it for the history behind the minimum payment warning.
Data
- Federal Reserve G.19 Consumer Credit. The release comes out monthly, and its credit card interest rates are quarterly figures. We use two of them: the average APR on all credit card accounts and the average APR on accounts assessed interest. The second one is the default “average APR” in our examples, currently 22.15% as of Q2 2026.
- New York Fed Household Debt and Credit Report. A quarterly report built from a nationally representative sample of Equifax credit data. We use its total US credit card balances, currently $1.26 trillion as of Q2 2026.
We refresh these statistics every quarter, after new data comes out. Each figure on the site shows its as-of date.
Consumer guidance
- CFPB: Credit cards. The CFPB’s plain-language guide to credit card terms and your rights. We use it to check how we describe APR, interest and statements.
- CFPB: How does my credit card company calculate the amount of interest I owe? The source for how issuers charge interest daily on your average daily balance, which is why a real statement differs a little from our monthly estimate.
- CFPB: What is credit counseling? What credit counseling organizations do. We point readers here when they need advice about their own situation.
- FTC: How To Get Out of Debt. The FTC’s guide to credit counseling, debt settlement and the warning signs of debt relief scams, including upfront fees.
- 16 CFR Part 255, the FTC Endorsement Guides (via Cornell’s Legal Information Institute) and the FTC’s companion guide, What People Are Asking. The rules for disclosing paid relationships. The site has none today; if it ever does, these set how the disclosure must appear.
Spot a source that’s out of date or a figure that doesn’t match? Email info@debtpayoffcalc.com.