Priority Fee

Overview

Under EIP-1559, a transaction can specify a maximum priority fee per gas and a maximum fee per gas. The base fee is determined by the protocol and burned on Ethereum, while the priority component is generally paid to the block proposer. Wallets often describe the priority fee as a tip.

The effective priority fee is not always equal to the maximum priority fee. It is limited by the remaining room between the transaction’s maximum fee and the current base fee. If the base fee rises close to the maximum total fee, the proposer tip can be lower than the sender’s stated priority cap.

Wallets estimate priority fees from recent block and mempool conditions. Fee suggestions are time-sensitive because demand, private order flow, and proposer policies can change quickly. Excessively low tips may delay inclusion, while excessively high tips increase cost without guaranteeing ordering against every competing transaction.

Payment systems should preserve maxPriorityFeePerGas, maxFeePerGas, baseFeePerGas, gasUsed, and effectiveGasPrice when available. These fields allow the actual priority component to be reconstructed and prevent a wallet estimate from being mistaken for the final amount charged.

Priority fees should be distinguished from protocol base fees, application service fees, and off-chain acceleration payments. Networks that use different fee markets may apply the term differently, so integrations should follow the active transaction type and official client behavior.

For example, a payment wallet may increase its priority-fee cap when an invoice is close to expiring, but it should compare the additional cost with the business value of faster inclusion. Operations teams should store the quoted cap and the confirmed effective tip separately. This distinction helps explain why a transaction confirmed quickly, why it was delayed, and whether the sender overpaid for urgency.