What Are Gas Fees? Why Crypto Transactions Cost Money
Gas fees pay the network to process your crypto transactions. Learn how they're calculated, why they spike and practical ways to pay less.
The first time you try to send tokens or use a crypto app, you'll likely see a "network fee" or "gas fee". Sometimes it's a few cents; sometimes it's surprisingly high. This guide explains what gas fees are, why they change and how to keep them under control.
What "gas" means
On Ethereum and many similar blockchains, every action — sending tokens, swapping on a decentralised exchange, minting an NFT — requires computing work from the network. Gas is the unit that measures that work. A simple transfer uses relatively little gas; a complex smart-contract interaction uses more.
The gas fee is the total you pay: the amount of gas used multiplied by the price per unit of gas. On Ethereum, gas prices are commonly quoted in gwei, a tiny fraction of one ETH (one billionth).
Where the money goes
Since an upgrade in 2021, Ethereum transactions include two parts:
- Base fee: set automatically by the network according to demand, and burned (permanently removed from circulation).
- Priority fee (tip): an extra amount paid to the validator who includes your transaction, encouraging faster processing.
Other blockchains structure fees differently, but the principle is the same: you pay the network to process and secure your transaction.
Why fees spike
Blocks have limited space. When many people want to transact at the same time — during a popular NFT mint, a market crash or a hyped token launch — they compete for that space, and fees rise. When activity is quiet, fees fall.
Why some networks are cheaper
- Layer-2 networks (sometimes called rollups) process transactions off the main Ethereum chain and then post compressed data back to it. This can make transactions far cheaper while still drawing on Ethereum's security.
- Other layer-1 blockchains make different design trade-offs that may result in lower fees.
Lower fees are attractive, but each network has its own security model, ecosystem and risks.
Gas fees you might pay in practice
| Action | Relative gas use |
|---|---|
| Sending the native coin (e.g., ETH) | Low |
| Sending a token | Low–medium |
| Token approval | Low–medium |
| Swapping on a decentralised exchange | Medium–high |
| Minting an NFT or complex DeFi actions | Medium–high |
What happens if you set the fee too low?
If the fee you offer is too low for current demand, your transaction may wait in the queue for a long time. Many wallets let you "speed up" (resubmit with a higher fee) or "cancel" a pending transaction. Failed transactions on some networks still consume gas, because the network did the work of processing them.
Practical ways to pay less
- Use a layer-2 or lower-cost network when the app you want supports it.
- Transact at quieter times. Fees often fall when fewer people are active.
- Batch actions instead of making many small transactions.
- Avoid unnecessary approvals, and revoke old ones only when worth the fee.
- Check whether a reward is worth claiming. A tiny airdrop may cost more in gas than it's worth.
Tip: Keep a small amount of the network's native token in your wallet. You can't pay gas with other tokens on most networks, so without it, your tokens can get "stuck".
Watch out for fake "fee" requests
Real gas fees are shown by your wallet and paid to the network. If a website, game or person asks you to send money to their address to "cover gas" before releasing your rewards or withdrawal, it's a scam.
Frequently asked questions
Why did I pay gas for a transaction that failed?
On networks like Ethereum, validators still performed computation before the transaction failed, so the gas used up to that point is charged. Common causes include setting the gas limit too low or price changes during a swap.
Do exchanges charge gas fees?
Trades inside a centralised exchange don't usually incur blockchain gas because they happen on the exchange's internal records. Withdrawals to an external wallet do involve a network fee, which the exchange passes on or replaces with its own withdrawal fee.
Can gas fees ever be zero?
Some apps sponsor gas fees on your behalf, and some networks have very low fees, but someone is still paying the network. Be wary of 'free' offers that later ask you to send money to cover fees.
Key takeaway
Gas fees are the cost of using a shared, secure network. They rise with demand, vary by network and can be reduced by choosing the right time and chain. Understanding them helps you judge whether an action — like claiming a small airdrop — makes financial sense.
Educational content only. This article is for general information and is not financial, investment, tax or legal advice. Crypto assets are highly volatile and you can lose money. Always do your own research and never share your seed phrase or private keys. Read our full disclaimer.
