Calculating Futures trading fees is actually not too difficult. With a simple formula, it can be expressed as:

Margin * Leverage * Fee rate = Trading fee

On Binance, the fee rate is 0.02% for Limit orders and 0.05% for Market orders. If you use $10 with 20x leverage, the trading fee will be:

10 * 20 * 0.05% = $0.1

This fee is calculated per execution. For example, if you open a position and then close it, the fee will be calculated for two executions, totaling $0.2. Only executed orders incur fees; pending orders that have not been executed are not charged.

The trading fees collected by the platform are used to cover their operational costs. They may reinvest these fees into their system or use them for personal purposes. This is a basic principle of business and is entirely normal.