What is a Gas Fee?

A gas fee is the price paid to validators (or miners) to include a transaction in a block. On Ethereum, gas is denominated in gwei (1 gwei = 10⁻⁹ ETH); the total fee equals gas amount × gas price. A simple transfer burns ~21,000 gas; a swap 100,000-300,000 gas; an NFT mint 200,000+ gas. EIP-1559 (August 2021) introduced an automatically adjusting base fee that is burned (creating deflationary pressure under load) and an optional priority fee (tip) that goes to the validator. Gas costs scale with network demand: NFT mint frenzies and high volatility push gas to hundreds of gwei. Optimization strategies include: (1) transacting outside peak hours (overnight, weekends), (2) routing through Layer 2 (Arbitrum, Optimism, Base), (3) batching transactions, and (4) keeping approval allowances bounded. Alternative L1s (Solana, Sui, Tron) advertise low gas at a decentralization/security trade-off. Tools such as Etherscan Gas Tracker and the MetaMask Gas Estimator help schedule transactions cost-effectively.