Ethereum transaction costs are measured in gas, a unit that quantifies computational work. Users pay for the actual gas consumed by a transaction multiplied by a price per unit of gas; the way that price is determined changed with the London upgrade and is important for users, builders, and policymakers who rely on Ethereum for financial and cultural services.
How fees are computed on-chain
Before the London upgrade, a transaction’s cost equaled the gas consumed multiplied by the gas price the sender chose, so the network used a first-price auction where users competed by raising gas price bids. The London upgrade introduced EIP-1559, a redesigned fee mechanism described by Vitalik Buterin of the Ethereum Foundation that separates fees into a base fee and a priority fee. The base fee is algorithmically set per block and burned (removed from supply), while the priority fee or tip compensates validators or miners. Concretely, the effective amount a sender ends up paying per unit of gas is the base fee plus the smaller of the user’s maximum priority fee and the difference between the user’s max-fee-per-gas and the base fee. The final on-chain cost equals gas used multiplied by that effective per-gas amount.
The base fee adjusts each block in response to demand: if blocks exceed the target gas usage, the base fee rises; if they are under target, it falls. The protocol limits the base-fee change per block so it cannot jump arbitrarily—this caps volatility without removing responsiveness to sudden demand shifts.
Causes, consequences, and broader context
High gas fees are primarily demand-driven: congestion from popular decentralized finance activity, NFT launches, or batch operations pushes base fees and priority fees higher. Miner or validator behavior and opportunities such as Miner Extractable Value or Maximal Extractable Value can also influence fee dynamics and user costs. EIP-1559’s burn mechanism introduced a monetary-policy effect: by burning the base fee, network activity can reduce ether supply growth and in some periods produce net supply reductions. The Ethereum Foundation’s post-upgrade materials and community analysis by core developers including Tim Beiko describe this as a structural change to fee flows and monetary issuance.
Human and territorial consequences are tangible. Elevated fees price out small-value users and limit participation from regions with lower average incomes, shaping who can economically interact with decentralized applications. Operationally, fees influence design choices: many applications route high-volume traffic to Layer 2 rollups or sidechains to keep per-user costs low. Environmental considerations changed after the Merge to proof-of-stake; the Ethereum Foundation reports a drastic reduction in energy consumption, so fee design now has less direct link to energy cost but continues to affect economic access and on-chain resource allocation.
For practitioners, the practical takeaway is that transaction cost equals gas used times the effective per-gas price set by the interplay of base fee and user-specified caps. Understanding EIP-1559’s mechanics helps users set sensible max fee and priority fee values and helps builders design UX and scaling strategies that reduce friction for diverse global users.