A gas fee is what you pay the network to process a transaction: gas used times the price per unit of gas
Gas measures the computational effort an operation needs on Ethereum. The fee equals the gas used multiplied by the price per unit, paid in ETH and quoted in gwei. It has two parts: a base fee set by the protocol, which is burned, and a priority fee, a tip to validators. A plain ETH transfer uses 21,000 gas; a token swap uses far more.
The unit that measures the computational effort needed to execute operations on Ethereum (ethereum.org). Fees are paid in ETH and quoted in gwei.
Calculate a gas fee
Pick the operation, then enter the gas price your wallet shows. Add the ETH price if you want the fee in your currency.
- 21,000gas for a standard ETH transferethereum.org
- 184,523gas ethereum.org lists for a Uniswap swapethereum.org
- 12.5%maximum change of the base fee from one block to the nextethereum.org
How is a gas fee calculated?
- Gas used
Each operation costs a fixed amount of gas. A swap runs more code than a transfer, so it uses more.
- Base fee
Set by the protocol for each block and burned, removed from circulation.
- Priority fee
A tip you choose so validators include your transaction sooner.
- Max fee
The most you agree to pay per unit. You are refunded the difference between it and the base fee plus tip.
What is the difference between gas limit and gas price?
Gas limit
- The maximum gas you are willing to consume.
- 21,000 is enough for a plain ETH transfer.
- If a transaction runs out of gas, its changes are reverted and the gas is still spent.
Gas price
- What you pay per unit of gas, in gwei.
- Base fee plus priority fee.
- Rises when many users compete for the same block.
Why are Ethereum gas fees so high right now?
Gas fees rise with demand, because users offer higher tips to outbid each other for space in the next block.
The base fee then follows: it can move up or down by at most 12.5% per block, depending on whether the previous block was above or below its target size.
Layer 2 networks are the main route ethereum.org names for lower costs.
A failed transaction costs nothing.
The gas fee is paid whether a transaction succeeds or fails (ethereum.org).
The whole fee goes to validators.
The base fee is burned. Only the priority fee, the tip, goes to validators.
Gas is a fee charged by the app.
Gas pays the network for processing. Any app or service fee is separate.
A higher gas limit means a higher fee.
You pay for the gas actually used. The limit is a ceiling.
Do other blockchains have gas?
- Tron: every transaction consumes Bandwidth, and smart contract calls such as TRC-20 transfers also consume Energy. Energy has no free quota, so TRX is burned for any part not covered by staked or delegated Energy.
- Solana: every transaction pays a fee in SOL, a per-signature base fee plus an optional prioritization fee. Half the base fee is burned and half goes to the validator.
That is why sending a token usually needs some of the network's own coin: ETH on Ethereum, TRX on Tron, SOL on Solana.
Gas and network fees on an instant swap
On SimpleSwap and ChangeNOW, the quoted amount includes the outgoing network fee for the coins sent to you. You may separately pay the network fee your own wallet charges when you send the deposit.
More on what is inside a quote in Swap fees and quotes.
Questions
What are gas fees in crypto?
Gas fees are what you pay a network to process a transaction. On Ethereum the fee equals the gas used times the price per unit of gas, paid in ETH.
Do I lose gas if my transaction fails?
Yes. The gas fee is paid whether the transaction succeeds or fails, and a transaction that runs out of gas has its changes reverted while the gas is still spent.
What is the difference between gas limit and gas price?
The gas limit is the most gas you allow a transaction to use. The gas price is what you pay per unit, the base fee plus your priority fee.
How do I get cheaper transaction fees on Ethereum?
Fees follow demand, so they are lower when the network is quieter. Layer 2 networks are the main route to lower costs.
What are energy and bandwidth on TRON?
They are Tron's resources. Every transaction uses Bandwidth, and smart contract calls such as TRC-20 transfers also use Energy.
If you have not staked TRX for Energy, TRX is burned to cover it.