If you follow the rules for using a credit card, you can never pay interest on it at all, even if the credit limit is fully spent: return the funds within an interest-free period and the next day you can use the card again for free

All credit cards with an interest-free period are limited in terms of credit limit, terms of interest-free use and type of transactions.

The grace period for a credit card is usually valid for non-cash purchases of goods and services and for paying bank fees (for example, for monthly card maintenance). Interest on purchases abroad or on foreign sites during the grace period is also not charged. But for many other transactions, the interest rate can be applied even during the grace period. These include:

withdrawing cash from ATMs;
transfers from card to card;
transfers to another bank;
quasi-cash operations - transfer of funds from a card to electronic wallets, trading platforms;
other operations, including within the grace period, if they go beyond the credit limit calculated in advance for you.
Another nuance is the start date of the grace period. Some credit organizations count it from the day when the credit card account becomes indebted, usually 2-3 days after the purchase, while others - from the reporting date. The first reporting date is usually indicated on the envelope with the card's pin code - this is the actual date of receipt of the card, and the subsequent ones - in the monthly account statement. In order not to get confused, install the mobile application - it provides information about the beginning of the grace period, the amount of debt in the interest-free period, the recommended date of debt repayment.

Credit Card Calculator will help you if you use your credit card regularly.