$USDC Ethereum Network (ERC - 20 Standard): The transaction fee is calculated based on the current 'Gas fee' of the network. The Gas fee is set by miners on the Ethereum network, and its price depends on the level of network congestion and the transaction confirmation speed chosen by the user. When initiating a transaction, the wallet automatically calculates the required amount of Gas, and the fee is typically expressed in stablecoins or ETH. Users need to confirm the total amount to be paid and the transaction fee.

• TRON Network (TRC - 20 Standard): Fee = Transaction size × Rate. The transaction size is measured in bytes and the rate is measured in SUN (the smallest unit of the TRON network). For example, if the transaction size is 200 bytes and the chosen rate is 10 SUN/byte, then the fee is 200×10 = 2000 SUN, which can then be converted to TRX to obtain the actual monetary value of the transaction fee.

Trading on cryptocurrency exchanges

• Calculated at a fixed rate: Some exchanges apply a fixed percentage rate for stablecoin transactions. For instance, the regular user fee rate for USDT trading on the OKEx exchange is 0.1% for market orders and 0.08% for limit orders. If 1 BTC is sold for 10,000 USDT entirely as limit orders, the fee would be 10,000×0.08% = 8 USDT; if entirely as market orders, the fee would be 10,000×0.1% = 10 USDT.