Wei to ETH Converter

Every amount on the Ethereum chain is a whole number of wei. A wallet shows ether because 1,500,000,000,000,000,000 is hard to read, but contracts, logs and node APIs return the long form, and developers have to move between the two constantly. This page converts between all the named units without rounding, and adds a small calculator for what a transaction costs.

The units

Wei is the smallest unit. A gwei, short for giga-wei and also called a shannon, is a billion wei; it is the unit in which gas prices are quoted. An ether is 10 to the power 18 wei, a quintillion. The older names fill the steps between: kwei (babbage) is a thousand wei, mwei (lovelace) a million, szabo a trillion (10¹²) and finney a quadrillion (10¹⁵). The page lists them all so you can see an amount in each at once.

Why exactness matters

A balance of 1.5 ether is 1,500,000,000,000,000,000 wei, nineteen digits. Standard floating-point numbers, the kind used by spreadsheets and ordinary scripting languages, carry about sixteen significant digits, so a tool that converts through them can show a value that is off in the last places. The converter holds the amount as a big integer and moves the decimal point by exact amounts, so nothing is lost. Input with more decimal places than the unit allows, such as 0.5 wei, is rejected with a message.

The fee calculator

The cost of a transaction is the gas it uses multiplied by the price paid for each unit of gas. Gas used is a whole number, 21,000 for a plain transfer of ether, and larger for contract calls. The gas price is entered in gwei. The page shows the fee in wei and in ether. Under EIP-1559 the price per gas is the sum of a base fee set by the network and a priority tip chosen by the sender, so enter that total as the price if you want to match a real transaction.

Using the page

Enter an amount, choose the unit it is in and the unit you want, and read the result. The table beneath lists the same amount in all seven units. The Swap button reverses the units. The price box asks for the price of one ether in your currency and multiplies; the page never fetches rates, so use a figure from a source you trust. Nothing is sent from your browser.

A worked example

The Sample button loads 1,500,000,000,000,000,000 wei. In ether it is 1.5; in finney 1,500; in szabo 1,500,000; in gwei 1,500,000,000. The gas box starts with 21,000 gas at 25 gwei, which gives a fee of 525,000,000,000,000 wei, or 0.000525 ether. Doubling the price to 50 gwei doubles the fee to 0.00105 ether, since the fee is proportional to the gas price.

Limits

The result is arithmetic on the numbers you type. The page does not read the network, so it knows nothing about current gas prices, the base fee of a block, refunds or the gas a contract call will really use. Use a wallet’s estimate or a node’s simulation for that. Negative amounts are not accepted, and amounts must be written as plain decimals.

Related tools

• Ethereum Address Checksum verifies the format of addresses.
• Satoshi to BTC does the same job for bitcoin units.
• Hex to Decimal reads the hexadecimal quantities that node APIs return.
• Number Base Converter converts between other bases.