Ethereum fee dynamics from London to the 4 million ETH burn

The London hard fork at block 12,965,000 in August 2021 replaced the legacy first-price auction with a dual-component fee mechanism. Users specify a maxFeePerGas and maxPriorityFeePerGas for Type 2 transactions. This change introduced a protocol-enforced base fee that the protocol burns, creating a direct link between network utilization and ETH supply reduction. This mechanism fueled the "ultra-sound money" narrative. By 2026, this process destroyed 4 million ETH. The protocol targets 15M gas per block with a 30M elastic limit. The base fee increases by up to 12.5% when the previous block exceeds 50% of the gas target and decreases when capacity falls below it. This mechanism ensures the protocol burns the base fee, which prevents miners from manipulating fees to extract more from users. The upgrade introduced a new transaction type, 0x02, which includes parameters like the chain_id, nonce, and access_list. Wallet developers and exchanges had to update their fee estimation logic to handle these new transaction envelopes.

The fee formula follows a strict calculation: Transaction fee equals gas used multiplied by the sum of the base fee and the priority fee. This structure makes fees more predictable for wallets but fails to lower fees during periods of intense demand.

The base fee adjusts algorithmically each block. If the previous block contains more than 50% of the target gas, the base fee increases. A simple ETH transfer requires 21,000 gas, while a complex DeFi swap might consume 200,000 or more. The BASEFEE opcode (0x48) allows smart contracts to read the current block’s base fee. You should monitor the 95th percentile fee spread if you want to avoid overpaying during congestion. The 12.5% adjustment per block compounds rapidly when blocks consistently exceed the target gas usage, which can lead to a situation where fees double in under a minute during sustained periods of heavy network congestion. The protocol requires users to set a maxFeePerGas to cover both the priority fee and the base fee. Because the base fee fluctuates based on block demand, users must account for the possibility that the fee rises after they submit a transaction.

Base fee volatility and MEV extraction define the modern fee landscape. Validators receive only the priority fee and any direct transfers. This shift makes MEV extraction a significant portion of validator income. This change altered block-building strategies because the base fee burn removes the 100% fee revenue model for miners. Failed or reverted MEV bundles incur a direct, unrecoverable cost due to the base fee burn. During the 2021 NFT boom, gas fees regularly exceeded $100 per transaction. Users face stuck transactions if they set the maxFeePerGas too low when the base fee rises. The protocol requires users to specify the maximum fee they will pay to cover both the priority fee and the base fee. The 12.5% maximum difference in base fee from block to block aims to maintain stability, but the compounding nature of these increases can still lead to rapid price spikes. MEV searchers must optimize bidding strategies. The reduction in miner revenue from the base fee also reduces the profitability of spam attacks designed to congest the network for competitive advantage. Will the increasing complexity of MEV strategies eventually destabilize the fee market for retail users?