[The Duke]

https://www.forbes.com/advisor/credit-cards/how-and-when-is-credit-card-interest-charged/

Search for "How Does Interest Work?"

Your own card may calculate/charge interest differently, but I've read this from multiple sources.

[Dr. Sivana]

Your link agrees with my point:

If a credit card balance is not paid in full by a payment due date, credit card companies begin charging interest

Millions pay the card in full every month before the due date, That due date is typically 20-25 days after you get billed. If you spend early in the cycle, you can get about 50 days of float.