In Ethereum’s execution fee market, the base fee is the required price per unit of gas for inclusion in a particular block. It is calculated by protocol rules, rather than individually negotiated with a validator. Other networks and resource markets can use different base-fee mechanisms.
Adjustment and burning
Ethereum adjusts the execution base fee according to the previous block’s gas usage relative to a target. Usage above the target increases the next block’s base fee; usage below it reduces the fee, subject to the protocol’s calculation and rounding rules.
The base-fee portion of a transaction’s payment is burned. A separate priority fee can compensate the block producer, so the base fee alone is not the transaction’s complete execution cost.
Reading a fee quote
Assume a transaction uses 21,000 gas, with a base fee of 30 gwei and an effective priority fee of 2 gwei. Its execution fee is 21,000 × 32 gwei, or 0.000672 ETH. This example excludes other resource or service charges.
A maximum fee per gas caps willingness to pay; it is not automatically the amount charged. If that cap is below a block’s base fee, the transaction cannot be included in that block. Meeting the base fee does not guarantee immediate inclusion.