What is Gas fees?
The transaction fee paid to use the Ethereum network, priced in tiny units of ETH called gwei.
Gas is the fee you pay for the network's computers to process your transaction, priced in tiny fractions of the chain's native coin (on Ethereum, in "gwei" — billionths of an ETH). Every action costs gas: simple transfers cost little, complex smart-contract interactions cost more, and the price of each unit floats with demand — busy network, expensive blocks.
Two practical consequences. First, gas is why small transactions can be uneconomic on Ethereum's main network during congestion, and why Layer 2 networks exist — same security neighbourhood, fraction of the fee. Second, gas is paid in the native coin, so you need a little ETH in a wallet even to move other tokens out of it — the classic beginner trap of "my funds are stuck because I can't pay the exit fee".
See it in practice
Related terms: Ethereum · Blockchain · Spread · full glossary
FAQ
Why did my $20 transfer cost $15 in gas?
Gas prices scale with network congestion, not transaction size — sending $20 and $20,000 costs the same. For small amounts, use quieter hours, a Layer 2 network, or a chain with lower fees.
Do all blockchains charge gas?
All charge transaction fees in some form — it's the spam defence and the payment to whoever secures the network. "Gas" is Ethereum's terminology; costs and models vary enormously between chains.
General information only, not financial advice. Definitions are maintained in our fact database and reviewed with the daily rebuild.