Free tool

Wei to Gwei to Ether Converter

Convert between every Ethereum and Monad denomination — wei, gwei, and ether — with exact, big-integer precision.

Wei is the smallest unit of ETH or MON; 1 ether = 1,000,000,000 gwei = 10^18 wei. This converter takes a value in any unit and shows it in all the others instantly, using big-integer math so there is no rounding error — the same denominations Monad uses because it is EVM-compatible.

Wei1000000000000000000
Kwei1000000000000000
Mwei1000000000000
Gwei1000000000
Szabo1000000
Finney1000
How it works

Ether (and Monad's MON) has no decimal type on-chain. The EVM only knows integers, so every amount is stored in wei — the smallest indivisible unit. One ether is exactly 10^18 wei, and one gwei ("giga-wei") is 10^9 wei. Gas prices are quoted in gwei because it is a convenient scale for fees, while smart-contract code deals in wei almost exclusively.

Converting by multiplying or dividing with JavaScript numbers breaks for large values, because numbers above 2^53 lose precision. This tool parses your input into a wei BigInt and formats back out, so a value like 123456789012345678 wei round-trips perfectly to ether and back.

Because Monad is EVM-compatible, MON uses the identical denomination ladder: 1 MON = 10^18 wei, fees are quoted in gwei, and the same converter applies when you deploy or interact with a token on Monad.

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FAQ

Common questions

How many wei are in 1 ether?
There are exactly 1,000,000,000,000,000,000 wei (10^18) in 1 ether. The same ratio applies to 1 MON on Monad.
How many gwei are in 1 ether?
1 ether equals 1,000,000,000 gwei (10^9). Gwei is the unit gas prices are usually quoted in.
What is gwei used for?
Gwei is the standard unit for expressing gas prices. A '20 gwei' gas price means each unit of gas costs 20 × 10^9 wei.
Does this converter work for MON on Monad?
Yes. Monad is EVM-compatible, so MON uses the same wei/gwei/ether denominations as ETH — the conversions are identical.
Why not just multiply by 10^18?
Multiplying with floating-point numbers loses precision past 2^53, corrupting large wei values. This tool uses big-integer math so every conversion is exact.
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