Wei / Gwei / ETH Converter

How Wei / Gwei / ETH Converter Works

Convert between Wei, Gwei, and ETH instantly. Ethereum unit converter with USD value — runs privately in your browser. Select your input and output formats, enter your value, and the tool converts it instantly in your browser with no server calls.

Understanding Ethereum Denominations

Ethereum uses a system of denominations similar to how traditional currencies have sub-units (cents, pence). The smallest unit is Wei, and the most commonly used unit is Ether (ETH). Between them sit several intermediate units, each named after influential cryptographers and computer scientists who contributed to the foundations of digital currency and cryptography.

The full denomination ladder spans 18 orders of magnitude. One Ether equals exactly 1,000,000,000,000,000,000 Wei (10¹⁸). This extreme precision is intentional — smart contracts on the Ethereum Virtual Machine (EVM) perform all arithmetic in Wei using integer math, completely avoiding the floating-point rounding errors that plague traditional financial software.

The Seven Ethereum Units

Wei (10⁰) — named after Wei Dai, creator of b-money — is the atomic unit. Every balance and transfer on-chain is stored in Wei. Kwei (10³), also called Babbage after Charles Babbage, and Mwei (10⁶), also called Lovelace after Ada Lovelace, are rarely used in practice but exist for completeness.

Gwei (10⁹), also known as Shannon after Claude Shannon, is the most important intermediate unit. It is the standard denomination for gas prices. When a wallet displays "base fee: 25 Gwei," it means each unit of gas costs 25 billion Wei. This keeps numbers human-readable — saying "25 Gwei" is far easier than "25,000,000,000 Wei."

Microether (10¹²), called Szabo after Nick Szabo (who conceptualized smart contracts), and Milliether (10¹⁵), called Finney after Hal Finney (Bitcoin's first recipient), bridge the gap to Ether (10¹⁸). These units occasionally appear in documentation and developer tools.

Example

How to Work Out an Ethereum Gas Fee in USD

This is the reason most people convert Gwei in the first place, and it is where the common mistake happens: 21,000 is a quantity of gas, not a price in Gwei. The two get multiplied together, they are not the same number. The formula is gas units × gas price (in Gwei) = total fee in Gwei, which you then convert to ETH and multiply by the ETH price.

Work a standard transfer through it. A plain ETH send always costs exactly 21,000 gas units. If the network gas price is 25 Gwei, the fee is 21,000 × 25 = 525,000 Gwei. Divide by 10⁹ to get 0.000525 ETH. At an ETH price of $2,500 that is about $1.31. Change only the gas price to 8 Gwei and the same transfer costs 168,000 Gwei, or roughly $0.42 — which is why timing a transaction matters more than anything else you can control. Contract interactions use far more gas than a plain transfer: a token transfer typically runs 45,000–65,000 gas and a Uniswap swap can exceed 150,000, so multiply accordingly. Paste your total into the converter above to move between Gwei, Wei and ETH at full 18-decimal precision.

EIP-1559: Base Fee, Priority Fee, and What Gets Burned

Since the London upgrade in August 2021, the gas price you pay is not a single number. It splits into a base fee set by the protocol, which every transaction in the block must pay and which is burned — permanently removed from supply rather than paid to anyone — and a priority fee, or tip, that goes to the validator for including you. The real formula is gas units × (base fee + priority fee). Using ethereum.org's own worked example: 21,000 gas at a 10 Gwei base fee with a 2 Gwei tip costs 21,000 × 12 = 252,000 Gwei, or 0.000252 ETH, of which 0.00021 ETH is burned and 0.000042 ETH reaches the validator. Your wallet also asks for a max fee, which is a ceiling rather than a charge: anything above the actual base fee plus your tip is refunded, so setting it generously protects you from a failed transaction without costing extra. The base fee moves algorithmically with how full recent blocks were, rising when demand climbs and falling when it eases. Source: ethereum.org — Gas and Fees.

Who Uses Which Unit?

Smart contract developers work in Wei because Solidity and the EVM handle only integers. Users and wallets display balances in Ether. Gas trackers and fee estimators report in Gwei. Understanding all three is essential for anyone interacting with the Ethereum ecosystem, whether you are sending a transaction, deploying a contract, or analyzing on-chain data.

This converter handles the full 18-decimal-place precision using string-based arithmetic, so you will never encounter rounding errors — even with very large Wei values or very small Ether fractions.

Why Your Wallet Charged Less Gas Than the Max Fee It Showed

The number a wallet shows before you sign is a ceiling, not a charge. Since EIP-1559 a transaction carries a max fee per gas and a max priority fee per gas; you are billed the block's base fee plus your priority tip, multiplied by the gas actually used, and everything between that and your max is returned in the same block. Two consequences matter when you reconcile a converted figure against your wallet history. First, a gas limit is not gas spent — a contract call with a 300,000 limit that only consumes 120,000 is billed on 120,000. Second, the base fee moves block to block, so the same conversion run a minute apart gives a different result even with the gas units unchanged. The fee mechanics are documented on ethereum.org, and any block explorer shows the base fee and gas used side by side on the receipt.

So when you check this converter against a past transaction, take the gas used and the effective gas price from the receipt — not the gas limit and max fee you approved.