The learning path
Gas is the unit of computational work on a blockchain. You pay gas units multiplied by a gas price, in the network native token. Fees exist to stop spam and to ration limited block space. The single biggest saving available is using a layer 2 network like Base or Arbitrum, where the same transaction costs a fraction of a cent instead of several dollars.
Why free would be worse
Imagine transactions cost nothing. One person with a script could submit millions of junk transactions per minute and nobody else would ever get through. The network would be unusable within hours.
Fees make that attack expensive, and they ration a genuinely limited resource. A block can only hold so much, so when demand exceeds supply you are bidding against everyone else who wants in.
What you are actually paying for
On Ethereum and similar chains, the fee has two parts:
| Component | What it is | Who gets it |
|---|---|---|
| Gas used | How much computation your transaction required. A transfer is 21,000. A swap might be 150,000 to 250,000 | Nobody, it is a measure |
| Base fee | A price per gas unit set automatically by network demand | Burned, permanently removed from supply |
| Priority fee | An optional tip to get included sooner | The validator who includes you |
Your total is roughly gas used, multiplied by base fee plus priority fee. A swap using 200,000 gas at 20 gwei costs 0.004 ETH.
Why fees spike
The base fee adjusts automatically. If the previous block was more than half full, it rises. If less, it falls. Sustained demand compounds this quickly, which is why a busy NFT mint or a violent market move can take fees from a few dollars to a hundred within minutes.
Five ways to pay less
Use a layer 2
This is the big one. The same swap costs several dollars on Ethereum and well under a cent on Base. Nothing else comes close to this saving.
Compare layer 2 networksWait for a quiet period
Check a gas tracker. Fees swing by 5x or more across a single day, and nothing about your transaction changes.
Approve exact amounts
Approving only what you are trading costs the same as unlimited but avoids a permanent open permission. Better security, identical fee.
Batch what you can
Some wallets and apps bundle several actions into one transaction. One base cost instead of three.
Pick a cheap chain to learn on
Practicing on Solana or Base means mistakes cost cents. Practicing on Ethereum mainnet means mistakes cost real money.
What a swap costs, by network
| Network | Typical simple transfer | Typical token swap |
|---|---|---|
| Ethereum | One to five dollars | Three to thirty dollars |
| Arbitrum | Under a cent | A few cents |
| Base | A fraction of a cent | Well under a cent |
| Solana | A fraction of a cent | A fraction of a cent |
| Bitcoin | One to ten dollars, varies widely | Not applicable |
Why failed transactions still cost
Gas pays for computation attempted. If your transaction runs and then hits a condition that makes it revert, the network still did that work, and you still pay. You keep your tokens, but the gas is gone.
Common causes: slippage exceeded during a fast move, an approval that was not high enough, or a contract condition that failed. The block explorer will usually tell you which.
Common questions
Why do I need ETH to move USDC?
Because the network charges for computation in its own native token, regardless of what you are moving. This catches nearly every beginner at least once. Always keep a small gas buffer.
What is gwei?
A billionth of an ETH. Gas prices are quoted in gwei because whole ETH would be an absurdly large unit for the numbers involved.
Can I set my own gas price?
Yes, most wallets allow it under advanced settings. Set it too low and you wait indefinitely. The defaults are usually reasonable, and the bigger saving is choosing a cheaper network.
Do all chains have gas fees?
Effectively yes, though they differ enormously. Solana charges a tiny fixed fee plus optional priority. Some layer 2s let apps sponsor your gas entirely, so you never see it.
Where to go next
Stuck on this one?
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