What are gas fees?
Gas fees are the cost you pay to have a transaction processed and recorded on a blockchain. Every action (a transfer, a swap, interacting with a smart contract) takes computational work, and gas is how you pay the network's validators for that work. The fee isn't fixed: it rises when the network is busy and falls when it's quiet, which is why the same swap can cost a few cents one hour and several dollars the next.
What determines the fee
A gas fee is roughly how much work the transaction takes × the current price per unit of work:
- Gas used: simple transfers are cheap; complex smart-contract interactions (multi-step swaps, bridging) use more.
- Gas price / network demand: when many people transact at once, the price per unit rises as users compete for limited block space.
- The chain you're on: Ethereum mainnet is typically the most expensive; layer-2 networks (like Base, Arbitrum, Optimism) and many alt-L1s are far cheaper.
You usually pay gas in the network's native token (ETH on Ethereum and its L2s, for example), which is why you need a small amount of the native token to transact even if you're mainly moving stablecoins.
How to pay less
- Use a layer-2 or low-fee chain for routine activity.
- Transact during quieter periods, when demand and prices are lower.
- Batch actions where possible so you pay for fewer separate transactions.
- Keep a little native token on each chain you use so transactions don't fail for lack of gas.
This is educational information, not financial advice.
Frequently asked questions
Why are gas fees so high sometimes?
Gas prices rise when many people are transacting at once and competing for limited space in each block. On busy networks like Ethereum mainnet this can push fees up sharply; the same action on a layer-2 network is usually much cheaper.
Why do I need ETH to move my USDC?
Gas is paid in the network's native token, not in the token you're moving. So even a stablecoin transfer needs a small amount of the native token (like ETH) in your wallet to cover the fee.
How can I reduce gas fees?
Use a layer-2 or low-fee chain for routine transactions, transact when the network is less congested, batch actions where you can, and keep a small native-token balance so transactions don't fail.