To convert ETH to Wei, multiply the ETH amount by 10^18; to convert Gwei to Wei, multiply by 10^9. Those powers of ten mean the decimal places can be shifted exactly, but an input with more precision than the unit can represent must be rejected rather than rounded. The Sats, Gwei & Wei Converter provides the unit conversion and lets you copy the result.
The unit relationships
Wei is the smallest denomination of ETH used in Ethereum accounting. One ETH equals 1,000,000,000,000,000,000 Wei, or 10^18 Wei. One Gwei equals 1,000,000,000 Wei, or 10^9 Wei; therefore one ETH is also 1,000,000,000 Gwei. Ethereum's technical introduction describes Wei and Gwei as denominations of ether, with Gwei commonly used for gas prices. Bitcoin units are separate: one BTC is 100,000,000 sats, and sats do not convert into Wei because they belong to different assets and networks. Ethereum's denomination guide explains the ETH units; Bitcoin's FAQ confirms the BTC-to-satoshi relationship. Bitcoin's unit is not interchangeable with Ethereum's.
The conversion equations are:
- ETH to Wei: ETH × 10^18 = Wei
- Gwei to Wei: Gwei × 10^9 = Wei
- Wei to ETH: Wei ÷ 10^18 = ETH
- Wei to Gwei: Wei ÷ 10^9 = Gwei
The calculator's ETH/Gwei-to-Wei path builds a whole-number string using integer arithmetic. It does not convert the value to a floating-point number and then round the result. It accepts up to 18 digits after the decimal point for ETH and up to 9 for Gwei. Wei accepts whole numbers only. An input that exceeds the unit's precision is not a valid exact Wei amount, so the tool returns no conversion instead of silently changing it.
Worked example: 0.025 ETH in Wei and Gwei
Suppose a wallet or transaction record shows 0.025 ETH and you need to enter the amount in Wei. Multiply by 10^18:
0.025 × 1,000,000,000,000,000,000
= 25,000,000,000,000,000 Wei
To express the same value in Gwei, divide the Wei total by 10^9, or multiply the ETH amount by 10^9:
0.025 × 1,000,000,000 = 25,000,000 Gwei
Check the result by reversing the conversion: 25,000,000,000,000,000 ÷ 10^18 = 0.025 ETH. Both calculations describe the same quantity. They do not describe the transaction's US-dollar value, gas limit, or gas fee. Those depend on additional inputs and, for a fiat estimate, an exchange rate.
You can also convert a small Gwei amount directly. For 21.5 Gwei, the calculator shifts the decimal nine places:
21.5 × 1,000,000,000 = 21,500,000,000 Wei
That is exactly 0.0000000215 ETH. The fractional Gwei digit is representable because a Gwei is 10^9 Wei. A value such as 21.0000000001 Gwei has ten digits after the decimal and would require a fraction of one Wei. The calculator rejects that input rather than rounding it to a different amount.
A practical conversion workflow
- Identify the asset and the unit shown by the wallet, exchange, or transaction field. ETH, Gwei, and Wei are Ethereum denominations; BTC and sats are Bitcoin denominations.
- Choose the input unit that matches the displayed amount. Do not type a number labeled Gwei into an ETH field just because both are ETH-denominated.
- Enter the decimal as a plain nonnegative number. The converter expects digits and an optional decimal point; it does not parse commas, currency symbols, signs, or scientific notation.
- Read the destination unit's full value before copying. Wei amounts often contain many digits, so confirm the asset, destination network, and amount field in the wallet or application where you will use it.
- Reverse the conversion as a sanity check when an amount is large or consequential. If the original ETH or Gwei amount does not come back, verify the input unit and decimal placement.
Use the calculator to convert sats, Gwei, and Wei. For exchanging one crypto asset denomination or currency quote against another, use the crypto converter. For estimating a transaction's network charge in crypto terms, see the crypto fee calculator; a denomination conversion alone does not calculate a fee.
Common mistakes
- Moving the decimal the wrong direction. Converting ETH to Wei multiplies by 10^18, so the number grows. Converting Wei to ETH divides by 10^18, so the number shrinks.
- Confusing Gwei with Wei. A Gwei contains one billion Wei. Writing 25,000,000 as Wei when the intended amount was 25,000,000 Gwei understates the amount by a factor of one billion.
- Mixing a fee rate with a fee amount. Gwei is commonly used to quote a gas price, while Wei is a denomination. Converting a gas price does not by itself calculate the amount paid; the transaction's gas use also matters.
- Assuming the tool will round extra digits. It deliberately refuses fractional Wei. If a source has unsupported decimal precision, check the original amount and units instead of deleting digits without understanding the effect.
- Treating BTC and ETH units as related. Sats and Wei are both small denominations, but there is no fixed conversion between them. Moving from BTC to ETH requires a market exchange rate, not a unit conversion.
- Copying a long integer without checking it. Group digits visually for review, then paste the ungrouped number into the receiving field if required. The comma separators in prose are for readability and are not part of the numeric input.
FAQ
How many Wei are in one Gwei?
One Gwei is 1,000,000,000 Wei (10^9). One ETH is 1,000,000,000 Gwei and 10^18 Wei.
Why does a converter reject a Gwei amount with ten decimal places?
The tenth fractional Gwei place is smaller than one Wei. Wei is an integer unit, so that value cannot be represented exactly as a whole number of Wei. The converter preserves exactness by refusing excess precision.
Is 0.000000001 ETH one Wei?
No. Since one ETH equals 10^18 Wei, 0.000000001 ETH equals 1,000,000,000 Wei, which is one Gwei.
Does converting to Wei tell me the gas fee?
No. It only changes the denomination of an amount. A transaction fee estimate needs the gas consumed and the applicable gas price, plus any context required by the wallet or network interface.
Can I convert sats to Wei?
There is no fixed unit conversion. Sats are fractions of BTC and Wei are fractions of ETH. A BTC-to-ETH exchange rate is needed to compare their market values.
Not financial advice. This guide explains denomination arithmetic, not whether or how to transact.