Transaction fee

Blocks have limited room, so users attach a fee to compete for inclusion. On Bitcoin the fee is the difference between a transaction's inputs and outputs and is priced by size in satoshis per virtual byte. On Ethereum and other EVM chains it is computed as gas used multiplied by a gas price, with part of it burned under EIP-1559 and the rest paid as a tip to the validator.

Fees are a core part of a network's security budget. They compensate block producers alongside newly issued coins and, on Bitcoin, are expected to become the main reward as the block subsidy keeps halving. Fee levels also serve as a demand gauge: spikes usually accompany market volatility, popular token launches or waves of inscriptions.

A fee does not scale with the amount sent: moving a large sum can cost the same as a small one, while a tiny payment may cost more in fees than it is worth. Setting the fee too low can leave a transaction stuck for hours, and exchange withdrawal fees are a separate charge set by the platform.