Gas Fee

Overview

Gas measures work; the fee prices that work

Ethereum uses gas to measure the computational and storage-related work a transaction is allowed to consume. This is not fuel purchased in a separate market: it is an accounting unit for network resource use. A user specifies fee parameters and a gas limit, while the transaction consumes a number of gas units. The amount paid depends on consumption and the effective price per gas unit. Many Ethereum transactions use a base fee plus an optional priority fee under EIP-1559-style pricing.

How the underlying system works

Ethereum transactions specify gas limits and fee parameters. Under its EIP-1559 fee model, the effective fee includes a protocol-determined base component and any priority fee according to the transaction type and network state. A transaction can consume gas even if the intended smart-contract operation reverts; execution resources were still used.

Gas costs matter for merchant payments involving ERC-20 tokens, contract interactions and treasury transfers. A wallet may hold enough stablecoins to pay an invoice but not enough ETH to send them. On other EVM networks the native gas asset and congestion conditions differ. Do not confuse gas spent on-chain with a payment provider's processing commission.

A simple illustrative fee calculation

Suppose an Ethereum transaction consumes 21,000 gas and the effective price is 20 gwei per gas. The fee is 420,000 gwei, equivalent to 0.00042 ETH. The dollar cost depends on ETH's market price at the relevant time. A token transfer or complex smart-contract call often consumes more gas than a basic ETH transfer. Even if a contract call reverts, the network may still charge for the computation that was attempted. This is why “the transaction failed” does not always mean “the gas fee was refunded.”

What merchants and customers must understand

The native network currency usually pays gas on Ethereum even when the asset being transferred is USDC or another ERC-20 token. Therefore a wallet may show enough stablecoins but refuse to send because it has insufficient ETH. Network congestion can raise the fee needed for timely inclusion, and a low-priority transaction can wait. The gas limit is a safety cap on computation, not a promise that the entire maximum will be charged. Keep gas costs separate from payment provider commissions when explaining checkout fees.

Further reading and related concepts

Reference documents: Ethereum.org — Transactions.

Related glossary topics: Network Fee, ERC-20, Ethereum.