How it works
Every transaction on Ethereum or similar smart-contract chains consumes gas, a unit measuring computational work. The total fee equals gas used times the gas price (paid in the native token, e.g. ETH). Higher gas prices push your transaction ahead of others in the queue. Lower prices mean longer wait or rejection during congestion.
Example
A simple ETH transfer uses about 21,000 gas units. At a gas price of 30 gwei (0.00000003 ETH per unit) and ETH at $3,000, the fee is 21,000 × 30 / 1e9 × $3,000 = $1.89. A complex DeFi swap can use 200,000+ gas units, pushing the fee to $20 or higher during congestion.
Why it matters
Gas fees compound across many small transactions, eroding edge for active strategies. Layer 2 networks (Arbitrum, Optimism, Base) settle to Ethereum at a fraction of the cost. Choosing the right chain or batching transactions can save thousands per year for active users.
