Gas is the unit that measures the computational work required to execute operations on the Ethereum network. Every transaction — sending ETH, swapping tokens, minting NFTs, deploying smart contracts — requires a certain amount of gas. Gas fees compensate validators who process and secure the network. Without gas, there would be no incentive to process transactions and spam attacks would be trivial. Gas is priced in Gwei (1 Gwei = 0.000000001 ETH), and the total fee you pay = gas used × gas price.

After EIP-1559 (August 2021), Ethereum gas fees have two components: the base fee and the priority fee (tip). The base fee is algorithmically set by the network based on block demand — it increases when blocks are more than 50% full and decreases when they're less than 50% full. This base fee is burned (permanently removed from circulation). The priority fee is an optional tip you pay to validators to prioritize your transaction. Total gas price = base fee + priority fee. Our tracker shows the suggested total gas price for each speed tier.

Choose based on urgency and the current market conditions. Fast (paid more) gets included in the next 1-3 blocks (~15-45 seconds). Standard gets included in 1-5 minutes. Slow can take 5-15+ minutes during busy periods but costs significantly less. During low-traffic periods (weekends, late night UTC), the difference between tiers shrinks dramatically — Slow and Fast may be almost the same price. For large trades or time-sensitive DeFi actions, use Fast. For regular transfers when time isn't critical, use Slow.

Ethereum gas prices are determined by supply (block space) and demand (transactions waiting to be processed). Prices spike during: NFT drops and mints, DeFi liquidation cascades, major price movements causing mass trading, new protocol launches, and airdrop claim periods. Prices drop on weekends, late-night UTC hours, and during quiet market periods. The EIP-1559 mechanism smooths out some volatility by automatically adjusting the base fee each block, but demand spikes can still cause 10-100x price increases.

Each transaction type requires a minimum gas limit: ETH transfer = 21,000 gas (fixed); ERC-20 token transfer ≈ 65,000 gas; Uniswap V3 swap ≈ 130,000–200,000 gas; NFT mint ≈ 150,000–300,000 gas (varies by contract); Smart contract deployment ≈ 300,000–2,000,000 gas. Your wallet (MetaMask, Rabby, etc.) estimates this automatically. Setting your gas limit too low will cause the transaction to fail and you'll still pay for the gas used. Setting it higher than needed is safe — you only pay for gas actually consumed.

Gwei is a denomination of ETH: 1 ETH = 1,000,000,000 Gwei (1 billion Gwei). Gas prices are quoted in Gwei because they're tiny fractions of ETH. To calculate USD cost: Gas Limit × Gas Price (Gwei) ÷ 1,000,000,000 × ETH price in USD. Example: 21,000 gas × 20 Gwei ÷ 1,000,000,000 × $3,000 = $1.26 per ETH transfer. Use our calculator above to compute costs instantly for any gas limit and price.

Ethereum gas prices are typically lowest: on weekends (Saturday and Sunday UTC), between midnight and 6am UTC on weekdays, and during low market volatility periods. Gas is most expensive during US trading hours (2pm–10pm UTC), major news events, token launches, and bear market liquidation cascades. Many users set gas alerts or check this tracker before initiating expensive DeFi transactions to save $10–$100+ in fees.

EIP-1559, activated in August 2021 as part of the London Hard Fork, fundamentally changed Ethereum's fee market. Before EIP-1559, users bid in a first-price auction — you guessed what to pay and often overpaid. After EIP-1559, there's a transparent base fee that adjusts automatically each block (±12.5% depending on whether the previous block was more or less than 50% full). The base fee is burned — reducing ETH supply. You add a priority fee tip to get faster inclusion. This makes fees more predictable, reduces overpaying, and introduced ETH's deflationary mechanism.