If you have ever tried to make an Ethereum transaction and balked at the fee, you have met gas. Gas is simply the cost of getting the network to do something for you — and understanding it helps you avoid overpaying.
Gas is computational fuel
Every action on Ethereum — sending tokens, swapping on an exchange, minting an NFT — requires computation from the network. Gas measures how much work an action takes. A simple transfer costs little gas; a complex smart-contract interaction costs more. You pay for the work you ask the network to do.
Why fees swing so much
Block space is limited, so when lots of people transact at once, they bid higher fees to get included sooner — like surge pricing. During quiet periods, fees fall. This is the same supply-and-demand dynamic we cover in How Crypto Trading Fees Work, applied to block space.
Gwei and the total cost
Gas prices are quoted in gwei, a tiny fraction of an ether. Your total fee is roughly the gas an action needs multiplied by the price per unit of gas. So a fee depends on both how busy the network is and how complex your transaction is.
How to pay less
- Time it: fees are often lower during off-peak hours
- Use a Layer 2: networks like Arbitrum and Base settle to Ethereum but cost a fraction
- Batch actions where possible, and avoid transacting during major market spikes
The bottom line
Gas is the price of computation on Ethereum, set by how busy the network is and how much work your transaction needs. Once you understand it, you can time transactions and use Layer 2s to keep costs down. For the bigger picture on fees, see How Crypto Trading Fees Work.
