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What is the base fee?
The base fee is the minimum price per unit of gas a transaction must pay to get into the next Ethereum block. The protocol sets it automatically from how full recent blocks were, and the base fee part of every fee is burned rather than paid to anyone.
What it means for you
You cannot bargain over the base fee; you can only pay it or wait for it to fall. It can rise from block to block when the network is busy, so a transaction whose max fee drops below the current base fee sits unconfirmed until the fee comes back down or the transaction is replaced.
How it works
Each block targets using half of the block gas limit. If the previous block used more gas than the target, the base fee rises; if less, it falls, by at most 12.5% per block. Because blocks may grow to twice the target, a short burst of demand produces bigger blocks and a climbing fee rather than an auction. The base fee multiplied by the gas used is destroyed, which removes that ETH from supply. When EIP-1559 began, the initial base fee was 1 gwei.
An example
Say the base fee is 10 gwei and every block is completely full. Each block can push it up 12.5%, so after four full blocks it is about 16 gwei (10 x 1.125^4). A transaction sent with a max fee of 15 gwei would stop qualifying partway through and wait until the base fee falls.
Sources: ethereum.org: Gas and fees, EIP-1559: Fee market change for ETH 1.0 chain, ethereum.org glossary · checked 4 October 2026
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