$GWEI GWEI (Gas Wei) is a denomination of the cryptocurrency Ether (ETH), used to measure the cost of transactions on the Ethereum blockchain. It's crucial for understanding transaction fees, especially with the network's shift to Proof-of-Stake. Monitoring GWEI fluctuations is essential for optimizing gas costs, as higher GWEI means more expensive transactions. Analyzing GWEI trends helps users predict network congestion and find optimal times for transactions, impacting the overall efficiency and cost-effectiveness of interacting with decentralized applications.