What gas is
On Ethereum (and similar blockchains), every action — sending tokens, swapping on a DEX, minting an NFT, deploying a contract — requires computational work from the network's validators. Gas is the unit that measures how much work a transaction needs.
Think of it like fuel for a car. A simple transfer (sending ETH from one address to another) uses relatively little gas. A complex DeFi transaction (multi-hop swap across three liquidity pools) uses a lot more. The more complex the operation, the more gas it consumes.
How the price is determined
Gas is priced in gwei (a tiny denomination of ETH — 1 gwei = 0.000000001 ETH). The gas price fluctuates based on network demand.
When the network is busy (a popular NFT mint, a market crash causing panic selling), gas prices spike because everyone is competing to get their transactions processed. When the network is quiet, gas drops to a few gwei.
The total fee you pay = gas used × gas price. A standard ETH transfer uses about 21,000 gas units. If the gas price is 30 gwei, your fee is 21,000 × 30 = 630,000 gwei = 0.00063 ETH. At $3,500/ETH, that's about $2.20.
A complex DeFi swap might use 200,000+ gas units. At the same 30 gwei, that's $21. During peak congestion with gas at 200+ gwei, the same swap could cost $140+.
Why gas fees spike
- Popular token launches. When a new token drops and thousands of people try to buy simultaneously, gas wars erupt. People bid up gas to get their transaction processed first.
- Market volatility. During sharp price moves, traders rush to sell or buy, flooding the network with transactions.
- NFT mints. Free mints on Ethereum can cause gas fees to spike to hundreds of dollars per transaction.
- Network congestion. Ethereum processes roughly 15-30 transactions per second. When demand exceeds that, a backlog forms and fees rise.
How to minimize gas fees
- Time your transactions. Gas tends to be lowest on weekends and in the early morning (UTC). Tools like etherscan.io/gastracker show current prices.
- Use Layer 2 networks. Arbitrum, Optimism, Base, and Polygon process transactions at a fraction of Ethereum mainnet costs. Many DeFi apps support them.
- Set a gas limit. Wallets like MetaMask let you set a maximum gas price you're willing to pay. Your transaction waits until gas drops to your level.
- Batch transactions. Some protocols let you combine multiple actions into one transaction, saving gas.
- Use gas-efficient protocols. Some DEXs and contracts are optimized for lower gas consumption than others.
Gas on other blockchains
Ethereum isn't the only chain with gas fees — but it's the most expensive. Here's a rough comparison:
- Ethereum: $1-50+ per transaction depending on complexity and congestion
- Arbitrum/Optimism: $0.10-1.00
- Polygon: $0.01-0.10
- Solana: $0.001-0.01
- BNB Chain: $0.05-0.30
The demo advantage
On a centralized exchange or demo platform like Korvex, gas fees don't apply — you pay a simple trading fee (0.1%) regardless of network congestion. This lets you focus on learning trading mechanics without the variable of gas costs. Once you move to on-chain DeFi trading, gas awareness becomes critical.