My first Uniswap swap cost more in gas than I felt comfortable admitting. The interface showed a friendly green button. The wallet popup showed a number that made me close the laptop and go for a walk. Nobody had mentioned that using DeFi on Ethereum mainnet in 2021 energy was like paying cover charge at a club you weren’t sure you wanted to enter.
Not a bank fee — a bid
Gas isn’t a percentage skimmed by a company. It’s payment for computation on a shared machine — the EVM running your transaction. Simple send: small job. Swap through three contracts: big job. More work, more gas units.
The gas price is what you offer per unit. When everyone’s rushing to transact, you bid higher or you wait. That’s why fees feel random: you’re competing in an auction you didn’t know you’d joined.
Failed transactions still cost gas. I learned that one on a reverting swap. The network tried; you pay.
Gwei and the mental model
Wallets quote gwei — billionths of an ETH. I stopped converting to dollars in real time and started asking: is this action worth doing on mainnet, or should I use an L2? For a $2,000 move, $15 gas is annoying. For a $30 experiment, it’s the whole experiment.
I also learned to keep spare ETH for gas. Sounds obvious. Less obvious when your wallet is 100% USDC and you can’t approve a swap because you have nothing to pay the approval with.
What I do differently now
Batch mental work on L2s. Save mainnet for when I care about the deepest settlement. Read the wallet preview — gas limit, max fee, priority fee — instead of muscle-memory clicking confirm. And I size positions so gas isn’t half the trade.
If someone tells you crypto is “nearly free,” ask which chain, which year, and which transaction. Gas is the honest price of on-chain action. Ignore it and you’ll fund a very expensive education.
I still wince at high gas days. But at least now I know what I’m wincing at — not a hidden tax, but a meter running while the shared computer does my bidding.