Credit card interests are computed based on the daily balances.

For example, your statement date starts on the 1st of the month, with your due date 21 days after it closes. Let's say you purchased an item that cost Php 100,000 on Dec 1. Then you paid Php 99,999 on Dec 31. On Jan 21, your interest would be:

Dec 1 - 30: Php 100,000 * 2%/31 * 30 days = Php 64.52 * 30 = Php 1,935.48

Dec 31: Php 1.00 * 2%/31 * 1 day = Php 0.0006

Total interest: Php 1,935.48

So even if you paid 99.999% of your bill during the last day of the month, the interest from your daily balances continued to accumulate. Unless you pay your bill in full every month, that interest will be computed daily.