What is the difference between wei, gwei, and ETH?

Wei is the smallest denomination of Ether (1 ETH = 10^18 wei). Gwei (gigawei) is 10^9 wei and is the unit most commonly used for gas prices. ETH is the human-readable unit used for larger amounts and wallet balances. Think of wei as satoshis and ETH as bitcoins.

What is a smart contract?

A smart contract is a program stored on the Ethereum blockchain that automatically executes when predefined conditions are met. Once deployed, the code cannot be changed (immutable). Anyone can call its public functions by sending a transaction. Smart contracts eliminate the need for trusted intermediaries in agreements.

What is an Ethereum wallet address?

An Ethereum address is a 20-byte (40 hex character) identifier derived from the public key of an ECDSA key pair, prefixed with 0x. For example: 0x742d35Cc6634C0532925a3b844Bc454e4438f44e. The checksum version (EIP-55) uses mixed case to detect typos. One private key controls one address.

What is the difference between wei, gwei, and ETH?

Wei is the smallest denomination of Ether (1 ETH = 10^18 wei). Gwei (gigawei) is 10^9 wei and is the unit most commonly used for gas prices. ETH is the human-readable unit used for larger amounts and wallet balances. Think of wei as satoshis and ETH as bitcoins.

What is a smart contract?

A smart contract is a program stored on the Ethereum blockchain that automatically executes when predefined conditions are met. Once deployed, the code cannot be changed (immutable). Anyone can call its public functions by sending a transaction. Smart contracts eliminate the need for trusted intermediaries in agreements.

What is an Ethereum wallet address?

An Ethereum address is a 20-byte (40 hex character) identifier derived from the public key of an ECDSA key pair, prefixed with 0x. For example: 0x742d35Cc6634C0532925a3b844Bc454e4438f44e. The checksum version (EIP-55) uses mixed case to detect typos. One private key controls one address.

What is Ethereum? — Smart Contract Platform Explained

Definition

Ethereum is a decentralized, open-source blockchain platform that enables the execution of smart contracts — self-executing programs stored on the blockchain whose terms are directly written in code. While Bitcoin is primarily a peer-to-peer payment system, Ethereum is a programmable blockchain platform that serves as the foundation for decentralized applications (dApps), DeFi protocols, NFTs, and DAO governance systems. Ether (ETH) is the native cryptocurrency used to pay for computation on the network.

How It Works

Ethereum's Ethereum Virtual Machine (EVM) is a Turing-complete runtime that executes smart contracts written in Solidity or Vyper. Each operation in the EVM costs a specific amount of "gas" — the unit measuring computational work. Users pay gas fees in Ether to miners/validators to execute transactions and contract calls. Since the Merge (2022), Ethereum uses Proof of Stake consensus rather than energy-intensive Proof of Work. Ether is denominated in wei: 1 ETH = 10^18 wei. Gwei (10^9 wei = 1 nanoether) is the standard unit for expressing gas prices.

Common Use Cases

▸Deploying and interacting with smart contracts for DeFi protocols (lending, swaps)
▸Minting and trading NFTs (non-fungible tokens) representing digital ownership
▸Building and using decentralized exchanges (DEXs) like Uniswap
▸DAO governance where token holders vote on protocol decisions
▸Issuing ERC-20 tokens for project fundraising and utility

Example

ETH Unit Conversion:
1 ETH     = 1,000,000,000 Gwei
1 ETH     = 1,000,000,000,000,000,000 Wei

Gas example:
gas_limit = 21,000 (simple transfer)
gas_price = 20 Gwei
tx_fee    = 21,000 × 20 Gwei = 0.00042 ETH

Related Tools

ΞETH Unit Converter

Convert between all Ethereum denominations: wei, kwei, mwei, gwei, szabo, finney, ether.

ΞEthereum Address Validator

Validate Ethereum wallet address format: 0x prefix, 40 hex chars, EIP-55 notes.

⛽Gas Price Converter

Convert between Ethereum gas price units: wei, gwei, kwei, mwei, and ether.

FAQ

What is the difference between wei, gwei, and ETH?: Wei is the smallest denomination of Ether (1 ETH = 10^18 wei). Gwei (gigawei) is 10^9 wei and is the unit most commonly used for gas prices. ETH is the human-readable unit used for larger amounts and wallet balances. Think of wei as satoshis and ETH as bitcoins.
What is a smart contract?: A smart contract is a program stored on the Ethereum blockchain that automatically executes when predefined conditions are met. Once deployed, the code cannot be changed (immutable). Anyone can call its public functions by sending a transaction. Smart contracts eliminate the need for trusted intermediaries in agreements.
What is an Ethereum wallet address?: An Ethereum address is a 20-byte (40 hex character) identifier derived from the public key of an ECDSA key pair, prefixed with 0x. For example: 0x742d35Cc6634C0532925a3b844Bc454e4438f44e. The checksum version (EIP-55) uses mixed case to detect typos. One private key controls one address.

Related Terms

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