Ethereum Gwei ETH Wei Converter

Ether, gwei and wei

Ethereum works with three main denominations, tied together by 1 ETH = 10⁹ gwei = 10¹⁸ wei. The wei, named after cryptographer Wei Dai, is the smallest indivisible unit. The gwei (giga-wei, or 10⁹ wei) is what you'll see when gas prices are quoted, and ETH is the unit people actually use for balances and transfers. To put it in numbers, 21,000,000,000 wei equals 21 gwei, which is 0.000000021 ETH. So when a gas price reads "30 gwei", each unit of gas is costing you 30 × 10⁻⁹ ETH. Under the hood Solidity always counts in wei, which is why msg.value is denominated that way.

Applications

If you write smart contracts in Solidity, literals like 1 ether get converted to wei for you. Wallets such as MetaMask and Rabby show gas in gwei while reporting your balance in ETH. DeFi protocols including Uniswap, Aave and Curve keep their accounting in wei. On the tooling side, ethers.js and viem rely on parseEther and formatUnits to move between the units, and Etherscan displays each transaction value in both ETH and wei.

FAQ

Why three units? Each one earns its keep. Wei sidesteps floating-point errors because everything stays in BigInt math, gwei keeps gas prices readable, and ETH is the friendly number you trade with.

Are there other denominations? A few do exist: kwei (10³), mwei (10⁶), microether (10¹²) and milliether (10¹⁵). You'll just about never run into them in practice.

Why is gas in gwei? Most of the time prices land somewhere between 10 and 200 gwei, so you get tidy whole numbers instead of strings of decimals.

Can I send fractions of wei? No. Wei is a whole number that can't be split any further; think of it as the atom of Ethereum's accounting system.