The calculation of the 0.5% interest on a credit card is actually very simple. This is equivalent to an annual interest rate of 5, and interest will accrue at this rate every day. The formula is: Interest = Principal × Interest Rate × Time. For example, if you have a credit card debt of 10,000 yuan, the daily interest is 10,000 yuan × 0.05 = 5 yuan. The monthly (assumed 30 days) interest is 10,000 yuan × 0.05 × 30 = 150 yuan. The calculation of interest is divided into two situations: the bank will charge the interest payable from the borrower, that is, the bank's income from lending funds; at the same time, the bank will also pay the interest payable to the depositor, that is, the cost of attracting deposits.

Interest plays a key role in economic activity. For enterprises, it affects business decisions, and enterprises will strive to reduce capital occupation costs to improve efficiency. For individuals, interest income is an important consideration in their choice of investment tools, which will affect residents' asset allocation decisions, which will have an impact on both macroeconomic regulation and microeconomic structure adjustment.

In general, the 0.05% interest on a credit card is calculated daily based on your loan balance. It is both a source of income for the bank and a fee that the user of funds needs to bear. Understanding the rules for calculating interest can help you better manage your personal finances.