How cards charge interest, what the fees mean, and how to pick one that fits.
A credit card is a revolving line of credit. Pay the statement balance in full by the due date and the grace period means you are charged no interest on purchases at all — the APR only starts costing you money once you carry a balance. Most US issuers apply interest daily, to an average daily balance, which is why a carried balance grows faster than the headline rate suggests.
Written for the United States. Terminology, protection limits and regulators differ between markets, so a guide from another country will not transfer cleanly.
Card interest is charged daily on an average balance, not monthly on the closing one. Understanding the grace period is what makes the difference between paying nothing and paying a lot.
The minimum payment is designed to keep an account current, not to clear it. Here is what that means in years and dollars.
Calculators
Run the numbers on your own situation.
How much interest will my credit card cost?
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