Gas fee
Gas is the fee for computation on a network. You pay for the work the network does rather than for the amount you send: a plain transfer is cheap, a swap through a smart contract costs more, and the price climbs when the network is busy.
How it works
Every operation has a price in units of gas set by its complexity. A plain ETH transfer costs 21,000 units, a DEX swap around 150,000, and operations touching several contracts run past 300,000.
The total is units multiplied by price per unit. That price is measured in gwei, billionths of an ETH, and is set by demand: when transactions pile up, block space is bid for and the price rises.
Since 2021 the fee splits into a base portion, which is burned, and a tip to the validator for priority. Raising the tip moves you up the queue without changing the base.
A worked example
A plain ETH transfer: 21,000 units of gas, an 18 gwei base fee, a 2 gwei tip, ETH at $2,400.
| 21,000 × 20 gwei | 0.00042 ETH |
| In dollars | $1.01 |
| The same at 80 gwei | $4.03 |
The same transfer costs four times more on a busy network, and a DEX swap burns roughly seven times the gas of a transfer. The amount is irrelevant: sending $10 and $10,000 costs the same.
How to pay less
- Watch the loadPeak and quiet hours differ by multiples. A transaction that can wait should.
- Use a Layer 2Arbitrum, Base and Optimism run the same operations for cents while still settling to Ethereum.
- Limit is not priceThe gas limit is a ceiling and the unused part comes back. The price per unit is what actually sets the bill.
- Read it before signingThe wallet shows the total before you confirm. A $40 fee on a $30 transfer is visible in advance.
- A stuck transaction can be pushedResending with the same nonce and a higher gas price replaces it. Simply waiting at a low price can take a very long time.