Ethereum units table: wei, gwei, finney, ether
Ether is divisible to 18 decimal places. The smallest piece, one wei, is 10⁻¹⁸ ETH, and every balance and transfer on Ethereum is stored as a whole number of wei. The other names are just powers of 1,000 in between. Only three matter day to day: ether for amounts, gwei for gas prices and wei for code.
| Unit | Other names | Wei | Ether | Typical use |
|---|---|---|---|---|
| Wei | smallest unit | 1 | 0.000000000000000001 | On-chain balances, transaction values, contract math |
| Kwei | babbage, femtoether | 10^3 | 0.000000000000001 | Rarely used |
| Mwei | lovelace, picoether | 10^6 | 0.000000000001 | Rarely used |
| Gwei | shannon, nanoether, nano | 10^9 | 0.000000001 | Gas prices (base fee and priority tip) |
| Szabo | microether, micro | 10^12 | 0.000001 | Legacy name, rarely used |
| Finney | milliether, milli | 10^15 | 0.001 | Legacy name, rarely used |
| Ether (ETH) | ETH | 10^18 | 1 | Prices, wallet and exchange balances |
The names honor cryptography and computing pioneers: Wei Dai, Charles Babbage, Ada Lovelace, Claude Shannon, Nick Szabo and Hal Finney. Libraries such as web3.js still accept all of them; Solidity kept only wei, gwei and ether and dropped finney and szabo in version 0.7.0.
Gwei to ETH conversion table (with transfer cost)
Gas prices are quoted in gwei per unit of gas. A plain ETH transfer always uses 21,000 gas, so the fee is 21,000 × gas price. The last column uses the live ETH price.
| Gwei | ETH | Wei | 21,000-gas ETH transfer at this gas price | Transfer in USD (live) |
|---|---|---|---|---|
| 0.05 | 0.00000000005 | 50,000,000 | 0.00000105 ETH | $0.00251 |
| 0.1 | 0.0000000001 | 100,000,000 | 0.0000021 ETH | $0.00503 |
| 0.5 | 0.0000000005 | 500,000,000 | 0.0000105 ETH | $0.03 |
| 1 | 0.000000001 | 1,000,000,000 | 0.000021 ETH | $0.05 |
| 5 | 0.000000005 | 5,000,000,000 | 0.000105 ETH | $0.25 |
| 10 | 0.00000001 | 10,000,000,000 | 0.00021 ETH | $0.50 |
| 50 | 0.00000005 | 50,000,000,000 | 0.00105 ETH | $2.51 |
| 100 | 0.0000001 | 100,000,000,000 | 0.0021 ETH | $5.03 |
Mainnet base fees have mostly been well under 1 gwei lately (median about 0.098 gwei from Aug 20 to Oct 15, 2026 in our block data). See today's number on the live gas tracker.
ETH to gwei and wei table
| ETH | Gwei | Wei | USD (live) |
|---|---|---|---|
| 0.0001 | 100,000 | 100,000,000,000,000 | $0.24 |
| 0.001 | 1,000,000 | 1,000,000,000,000,000 | $2.39 |
| 0.01 | 10,000,000 | 10,000,000,000,000,000 | $23.93 |
| 0.1 | 100,000,000 | 100,000,000,000,000,000 | $239.33 |
| 1 | 1,000,000,000 | 1,000,000,000,000,000,000 | $2,393.29 |
| 10 | 10,000,000,000 | 10,000,000,000,000,000,000 | $23,932.90 |
Token decimals converter (USDC, USDT, WBTC, DAI)
ERC-20 tokens use the same trick as ether: the contract stores whole numbers and a decimals value says where the decimal point goes. USDC and USDT on Ethereum use 6 decimals, WBTC uses 8, and DAI and WETH use 18. Paste a raw amount from a block explorer, an event log or an approval to see the real token amount.
Always confirm a token's decimals from its contract (the decimals() function, shown under Read Contract on Etherscan). The same ticker on another chain can use different decimals.
How to convert Ethereum units by hand
- Gwei to ETH: move the decimal point 9 places left. 25 gwei = 0.000000025 ETH.
- ETH to gwei: move it 9 places right. 0.004 ETH = 4,000,000 gwei.
- Wei to ETH: move it 18 places left. 2,500,000,000,000,000 wei = 0.0025 ETH.
- Wei to gwei: move it 9 places left. 21,000,000,000 wei = 21 gwei.
- Any unit to USD: convert to ETH first, then multiply by the ETH price.
From gwei to a real transaction fee
A wallet's gas price is in gwei per unit of gas, not a total. The total fee is gas used × (base fee + priority tip), then divided by one billion to get ETH. ethereum.org's worked example: 21,000 gas × (10 + 2) gwei = 252,000 gwei = 0.000252 ETH. Token transfers use more gas (about 45,000 to 46,000 for USDT or USDC in our October 2026 sample) and swaps more still. The gas fee estimator and gas fees guide cover the details, including why layer 2 networks are cheaper.
Common unit mistakes that cost money
- Typing ETH where a field wants gwei (or the reverse). A custom gas price of 1 means 1 gwei, not 1 ETH. Read the unit label before you confirm.
- Wrong token decimals. Treating a 6-decimal USDC amount as 18-decimal makes it look a trillion times smaller. Always read decimals() from the contract.
- Unlimited approvals that look like gibberish. An allowance of 115792089237316195423570985008687907853269984665640564039457584007913129639935 is the maximum uint256, which means unlimited spending. Here is how to review and revoke approvals.
- Rounding in spreadsheets and code. Floating-point numbers are exact only up to about 0.009 ETH expressed in wei. Keep wei as text or BigInt.
- Assuming the same amount on every network. The units are the same on Ethereum layer 2s, but the asset may not be: check the network and token contract before sending, and verify the destination with the address checker.
ETH unit converter FAQ
How many wei are in 1 ETH?
1 ETH = 10^18 wei, which is 1,000,000,000,000,000,000 wei (one quintillion). Wei is the smallest unit of ether, and balances and transaction values are stored on-chain as whole numbers of wei.
How do I convert gwei to ETH?
Divide the gwei amount by 1,000,000,000 (10^9). 1 gwei = 0.000000001 ETH and 50 gwei = 0.00000005 ETH. To go the other way, multiply ETH by one billion: 1 ETH = 1,000,000,000 gwei.
How do I convert wei to gwei?
Divide wei by 1,000,000,000. One gwei is exactly 1,000,000,000 wei, so 21,000,000,000 wei is 21 gwei. Wei to ETH is a division by 10^18.
What is gwei used for?
Gas prices. Since EIP-1559, the fee per unit of gas is a base fee plus a priority tip, both quoted in gwei. Fee in ETH = gas used × (base fee + tip) in gwei ÷ 1,000,000,000. A 21,000-gas ETH transfer at 0.1 gwei costs 2,100 gwei, or 0.0000021 ETH.
How much is 1 gwei in US dollars?
One gwei is one billionth of an ETH, so its dollar value is the ETH price divided by 1,000,000,000. At an ETH price of $2,400, 1 gwei is $0.0000024. The converter on this page uses the live Coinbase ETH/USD rate.
What are finney and szabo?
Older named units. One finney is 10^15 wei (0.001 ETH) and one szabo is 10^12 wei (0.000001 ETH), named after Hal Finney and Nick Szabo. You rarely see them today; Solidity removed the finney and szabo suffixes in version 0.7.0, although libraries like web3.js still accept them.
Why does my token amount look like a huge number?
ERC-20 contracts store whole numbers of base units, and the token’s decimals value says where the decimal point goes. USDC has 6 decimals, so a raw value of 1500000 is 1.5 USDC. An 18-decimal token shows 1 token as 1000000000000000000. Use the token decimals converter to translate.
Why not use a spreadsheet or regular JavaScript numbers for wei?
Standard floating-point numbers are only exact up to 9,007,199,254,740,991 (2^53 − 1). In wei that is only about 0.009 ETH, so larger values silently lose precision. This converter uses BigInt integer math, the same approach as the parseUnits and formatUnits helpers in ethers.js.
Is this ETH converter safe to use?
Yes. Everything runs in your browser, nothing you type is sent to GrowYourEthereum, and there is no wallet connection. The only network request is the public Coinbase ETH/USD exchange rate used for the dollar column. Never paste a seed phrase or private key into any website.
Sources
- ethereum.org: Technical intro to ether (denominations of ether)
- Solidity docs: Ether units (wei, gwei, ether; finney and szabo removed in 0.7.0)
- web3.js: fromWei and the full list of unit names
- ethers.js v6: Unit conversion (parseUnits, formatUnits)
- EIP-20: Token standard (decimals)
- EIP-1559: Fee market change (base fee and priority fee)
- MDN: Number.MAX_SAFE_INTEGER
- Coinbase: public exchange-rates API (ETH/USD)
Educational tool. Unit conversions are exact; USD values use a live third-party rate and are estimates. Not financial advice. GrowYourEthereum is independent and not affiliated with Coinbase or any wallet. Published October 17, 2026.