Understanding Ethereum Gas Fees: A Complete Guide
Ethereum gas fees are the cost you pay to execute transactions on the Ethereum network. Every action — sending ETH, swapping tokens on Uniswap, minting an NFT, or interacting with a smart contract — consumes a specific amount of gas. The total fee formula is: Gas Fee = Gas Units × (Base Fee + Priority Fee).
How Much Gas Do Different Transactions Cost?
Simple ETH transfers use exactly 21,000 gas units. ERC-20 token transfers use 65,000 gas. Uniswap swaps typically use 150,000 gas. NFT mints range from 100,000 to 400,000 gas. Smart contract deployments can use 500,000+ gas.
Layer-2 Solutions: Dramatically Lower Gas Fees
Ethereum Layer-2 networks (Arbitrum, Optimism, Base, Polygon) reduce transaction costs by 90–97%. A transaction costing $5 on Ethereum mainnet may cost under $0.20 on Arbitrum.
When Are Gas Fees Cheapest?
Gas fees are typically lowest during off-peak hours: early morning UTC (midnight–6 AM UTC) and weekends. During major DeFi events or market volatility, gas can spike 10–50x.
Frequently Asked Questions
What happens to gas fees on Ethereum?
Since EIP-1559, the base fee portion of each transaction is permanently burned (destroyed), reducing ETH supply. The priority fee (tip) goes to the validator.
Can I get a gas fee refund if my transaction fails?
No — failed transactions still consume gas because validators spent computational resources processing them. You pay the gas fee even if the transaction reverts.
What is the cheapest way to send ETH?
The cheapest option is using a Layer-2 network like Arbitrum or Optimism. For mainnet transfers, transact during low-congestion periods (late night UTC).