The calculation formula of interest tax: interest tax = interest * interest tax rate. my country's current so-called "interest tax" actually refers to the tax items of "interest, dividends and bonus income" of personal income tax, which mainly refers to the personal income tax levied on the interest income obtained by individuals saving RMB and foreign currencies in China. The levy, suspension or reduction of personal income tax (interest tax) on savings deposit interest income has a certain regulatory function on the economy. Interest taxes are common in many countries around the world.