Every operation a transaction performs has a fixed cost in gas units, and the total is multiplied by the price a user offers per unit. A simple transfer is cheap; a transaction touching several contracts costs many times more. The fee compensates validators and, just as importantly, prevents anyone from spamming the network with computation for free.
Gas price is set by competition for limited block space, so fees spike when the network is busy and fall when it is quiet regardless of the transaction's own complexity. This is what makes small transactions uneconomic at peak times and why layer-2 networks, which settle many transactions to the main chain in batches, exist.
Why are gas fees sometimes so high?
Block space is limited and allocated by auction. When many people transact at once, the price per unit of gas rises until demand fits the available space — the cost tracks congestion, not the value being sent.
Last updated October 17, 2026