What are wei and gwei?
Ether, like Bitcoin, is divisible into much smaller units than the whole coin. The smallest is wei, named after Wei Dai, an early cryptographer whose work influenced Ethereum. One ETH equals 1,000,000,000,000,000,000 wei — that is 1018, or a quintillion. Ethereum tracks every balance and transfer internally in wei because integer math on the smallest unit avoids rounding errors that floating-point decimals would introduce.
Between wei and ETH sits gwei (gigawei), equal to 1,000,000,000 wei or 0.000000001 ETH. Gwei is the unit you see most often in wallets, because Ethereum gas prices are quoted in it. A gas price of "20 gwei" is far easier to read than "20,000,000,000 wei" or "0.00000002 ETH." This converter moves cleanly between all three units and shows the dollar value of each at the live market price.
How to use this converter
- Type an amount into the amount field.
- Pick the unit that amount is in — wei, gwei or ETH.
- The Ethereum price auto-fills with the live market rate on load. Leave it for the current value or type your own price.
- Read the results: the USD value at the top, plus the same amount expressed in ETH, gwei and wei so you can copy whichever unit you need.
How the units convert
Everything is normalised to ETH first, then scaled out to the other units and to dollars:
The conversion factors — 1e9 and 1e18 — are fixed by the Ethereum protocol and never change. Only the ETH price moves, which is why a live rate matters for the dollar figure. Because wei and gwei totals can be enormous, the calculator formats them as full integers with thousands separators rather than scientific notation.
Worked example
Enter 1 with the unit set to ETH, at an Ethereum price of $3,000. Normalised to ETH that is simply 1 ETH. Scaling out: gwei = 1 × 1e9 = 1,000,000,000 gwei, and wei = 1 × 1e18 = 1,000,000,000,000,000,000 wei. The dollar value is 1 × 3,000 = $3,000.00 — exactly what the calculator shows on load with its default inputs. Switch the unit to gwei with the same amount of 1 and the value collapses to 0.000000001 ETH, a tiny fraction of a cent — useful for sanity-checking a gas estimate.
Handy Ether unit reference
- 1 ETH = 1,000,000,000 gwei = 1,000,000,000,000,000,000 wei
- 1 gwei = 1,000,000,000 wei = 0.000000001 ETH
- 1 wei = 0.000000000000000001 ETH (10-18)
- 21,000 gas at 20 gwei = 420,000 gwei = 0.00042 ETH (a typical simple transfer fee)
These conversions are exact and independent of price. Only the dollar value of each changes with the market.
Why developers and traders use a wei converter
Smart-contract developers work in wei constantly — token amounts, transfer values and gas calculations are all expressed in the base unit, and a misplaced zero in an 18-decimal number is an easy and costly mistake. Quickly converting wei to ETH (and to dollars) is a fast way to verify that a contract call is sending the amount you intended. Traders and ordinary users reach for the gwei side to read gas prices, estimate what a transaction will cost before they confirm it, and decide whether to wait for the network to quiet down.
Common mistakes
- Counting the wrong number of zeros. Wei has 18 decimals; gwei has 9. Mixing them up is the classic Ethereum error — let the converter handle the exponents.
- Confusing gwei with ETH on gas. A "30 gwei" gas price is 0.00000003 ETH per unit of gas, not 30 ETH. The total fee is gas units × gwei price, then converted to ETH.
- Using a stale ETH price. Ether is volatile; an old quote can misstate a dollar value by several percent. The live field keeps you current.
- Ignoring fees and spread. The converter shows the mid-market value. Buying, selling or moving ETH on-chain also costs the exchange spread, trading fees and gas.
From units to a position
Once you know what your ETH is worth, you can plan around it. If you intend to trade rather than hold, size the position to a fixed share of risk with our position size calculator, check the downside with the liquidation calculator, and value satoshis the same way with the satoshi to USD converter. Reputable exchanges publish clear fees and support on-chain ETH withdrawals to your own wallet.