eth_getBlockByNumber, eth_maxPriorityFeePerGas, and eth_gasPrice on each chain's public RPC. USD prices come from CryptoCompare's open endpoint. No accounts, no signups, no API key.Total fee = gas units × (base fee + priority fee). EIP-1559 set the base fee per block; the priority fee is an optional tip to validators. Multiply by the number of gas units the transaction consumes (e.g. 21,000 for a plain ETH transfer) to get the cost in wei.
No. This calculator shows L2 execution gas only. Optimistic and ZK rollups also charge an L1 data fee to post batches to Ethereum, which can dominate the total cost when L1 gas is high. Read the dedicated chain explorer for the full breakdown of any specific transaction.
BNB Chain has not adopted EIP-1559. There is a single gasPrice rather than a basefee + tip split. We surface the unified gas price returned by eth_gasPrice instead.
Gas prices auto-refresh every ~12 seconds. USD prices refresh every 90 seconds. Switching chains triggers an immediate fetch.