Gas Fee Estimator

Gas is the unit of computational work on EVM-style chains. A transaction's cost equals gas used multiplied by gas price (gwei), denominated in the chain's native token. Ethereum L1, Base (an Ethereum L2), and Cosmos chains each price differently — Cosmos uses a fee unit rather than the EVM model.

This estimator pulls live gas prices and returns expected fees in gwei, native token, and USD for common transaction types.

Gas was introduced in the original Ethereum yellow paper as a way to price computation, storage, and bandwidth uniformly. Each EVM opcode has a fixed gas cost; a transaction's total gas is the sum of opcodes executed plus 21,000 base for the transaction itself. EIP-1559 (London hardfork, 2021) split gas price into a base fee (burned) and a priority tip (paid to validators), with base fee adjusting algorithmically to target 50% block fullness. L2 rollups (Arbitrum, Optimism, Base) inherit the EVM gas model but charge an additional L1 data fee for posting transaction data to Ethereum.

A worked example: at the time of writing, an ETH transfer on mainnet costs 21,000 gas at a typical 25 gwei base fee plus 2 gwei tip — total 21,000 × 27 × 10⁻⁹ = 0.000567 ETH, roughly $1.40 at $2,500/ETH. The same transfer on Base costs about 21,000 gas at 0.001 gwei — total 0.0000000021 ETH, well under a penny, plus a small L1 data charge. A Uniswap v3 swap consumes around 150,000 gas; on mainnet that's $10–15 at busy times, on Base under $0.10. Cosmos chains skip the gas-market entirely — TX charges a flat fee of about 5,000 utx per transaction, set by validator governance.

Limitations: the estimator shows current gas prices, not what your transaction will actually pay. Gas price is set when you sign and broadcast; if mempool conditions change in the meantime, the actual fee differs. Wallets typically pad gas limits by 10–20% to handle execution variance — unused gas is refunded. The estimator's USD figure depends on the price oracle's freshness; volatile token prices can shift the dollar cost between estimate and execution.