Gas is a meter, not a mystery

Thousands of computers have to run your transaction and store the result. If that were free, someone would loop forever and stall the machine. Gas is the unit of work. A simple ETH transfer costs 21,000 gas. A complex contract call can cost far more.

You do not buy “gas tokens.” You set a price you are willing to pay per unit of gas, in ETH. Since 2021 Ethereum has used a base fee that rises and falls with demand, plus an optional tip. The base fee is burned (destroyed). The tip goes to the validator who includes your transaction.

When lots of people want in at once — a popular mint, a market panic — the base fee climbs. Your transfer still works; it just costs more, the way a taxi costs more in the rain. Layer-2 networks (cheaper side-streets that still settle back to Ethereum) exist largely because of this.

Wallets estimate the fee before you sign. If you set the limit too low, the transaction can sit pending or fail — and a failed transaction can still cost gas, because the network did the work of trying.