Ever wondered what the smallest part of a Bitcoin or Ethereum is called? This guide explains the terminology for cryptocurrency units — from coins and tokens to satoshis, wei, and beyond — in plain, practical language.
At the highest level, a unit of cryptocurrency is simply called a coin or a token, depending on the context. But the terminology runs much deeper. Each cryptocurrency has its own naming conventions for its base unit and its fractional denominations — much like how the dollar has cents or the pound has pence.
For example, the base unit of Bitcoin is one bitcoin (BTC), but the smallest indivisible unit is called a satoshi (0.00000001 BTC). Ethereum’s base unit is one ether (ETH), and its smallest unit is called wei (10⁻¹⁸ ETH). Different blockchains use different names and decimal places, which can be confusing for newcomers.
One of the first distinctions to understand is the difference between a coin and a token. While both are units of cryptocurrency, they are not the same.
A coin is a cryptocurrency that operates on its own native blockchain. Examples: Bitcoin (BTC) on the Bitcoin blockchain, Ether (ETH) on Ethereum, and Solana (SOL) on Solana. Coins are typically used as a store of value, medium of exchange, or to pay network fees.
A token is a unit of value that is built on top of an existing blockchain, usually via smart contracts. Examples: USDC, UNI, or LINK (which run on Ethereum). Tokens can represent assets, utility, governance rights, or even real-world items like art (NFTs).
In everyday conversation, people often use “coin” and “token” interchangeably. But technically, a token cannot exist without a host blockchain, while a coin is the native asset of its own chain. This distinction affects how units are named and how they function.
Both coins and tokens have their own unit names and fractional denominations. The fractional units are where things get more specific and interesting.
Every cryptocurrency has a smallest indivisible unit — the atomic unit that cannot be subdivided further on that network. These tiny units have their own names, and they are essential for understanding how value is measured and transferred.
Named after Bitcoin’s pseudonymous creator, one satoshi equals 0.00000001 BTC (one hundred-millionth of a bitcoin). This means Bitcoin can be divided into 100 million satoshis. Satoshis are the standard unit for microtransactions and are commonly used to quote prices for smaller amounts.
Ethereum’s smallest unit is the wei (10⁻¹⁸ ETH). One ether equals 1,000,000,000,000,000,000 wei. For practical purposes, Ethereum also uses gwei (giga-wei), which equals 10⁻⁹ ETH. Gas fees are typically quoted in gwei, making it the most frequently used denomination for transaction costs.
Under the hood, blockchains do not process “dollars” or “BTC” in the way humans think. Instead, they work with integer values of the smallest unit. For example:
This integer-based accounting prevents rounding errors and ensures exact amounts are recorded. Wallets and exchanges handle the conversion between human-readable units and the underlying integer values automatically — but understanding this helps you read transaction data and avoid confusion.
Different denominations exist to make it easier to talk about different scales of value. You would not say “0.00000001 BTC” in casual conversation when you can say “one satoshi.” Similarly, quoting gas fees in wei would be unwieldy; gwei strikes a balance between precision and readability.
The table below compares the unit systems of the most prominent cryptocurrencies. Use it as a quick reference when you encounter different denominations.
| Cryptocurrency | Base Unit | Smallest Unit | Decimal Places | Common Intermediate Unit |
|---|---|---|---|---|
| Bitcoin (BTC) | 1 BTC | Satoshi (0.00000001 BTC) | 8 | — (or mBTC = 0.001 BTC) |
| Ethereum (ETH) | 1 ETH | Wei (10⁻¹⁸ ETH) | 18 | Gwei (10⁻⁹ ETH) |
| Litecoin (LTC) | 1 LTC | Photon (0.00000001 LTC) | 8 | — |
| Cardano (ADA) | 1 ADA | Lovelace (0.000001 ADA) | 6 | — |
| Dogecoin (DOGE) | 1 DOGE | 1 DOGE (no official subdivision) | 8 (display only) | — |
| Binance Coin (BNB) | 1 BNB | Jager (0.00000001 BNB) | 8 | — |
Note: Decimal places and unit names are defined by each blockchain’s protocol. Some tokens may use up to 18 decimal places if they follow the ERC-20 standard.
Understanding the correct terminology for cryptocurrency units is not just trivia — it has practical implications for how you interact with the ecosystem.
When you view a transaction on a block explorer, the amounts are often displayed in the smallest unit (e.g., wei or satoshis). If you do not recognize the denomination, you might misinterpret the value being transferred.
On Ethereum, gas fees are quoted in gwei. If you think in terms of ETH, the numbers can seem tiny and confusing. Understanding that 50 gwei = 0.00000005 ETH helps you estimate costs more clearly.
Whether you are in a community forum, on social media, or speaking with a support agent, using the correct units avoids misunderstandings. Saying “I paid 200 gwei” conveys a specific, widely understood meaning.
When tracking your portfolio, you might see balances in both base units and smaller denominations. Knowing the relationship between them helps you spot errors or discrepancies in your wallet or exchange interface.
Use this checklist to ensure you understand the unit system of any cryptocurrency you interact with.
Going through this checklist for each new cryptocurrency you encounter will build your confidence and help you avoid unit-related errors.
Priya wants to send 0.05 ETH to a friend. She opens her wallet, enters “0.05” in the ETH field, and confirms. The wallet automatically converts that to wei behind the scenes: 0.05 × 10¹⁸ = 50,000,000,000,000,000 wei.
She also needs to set a gas fee. The wallet suggests 25 gwei. Priya knows that 25 gwei = 0.000000025 ETH. For a standard transfer, the gas limit might be 21,000 units, so her total gas cost in ETH would be 21,000 × 0.000000025 = 0.000525 ETH.
Priya confirms the transaction and later checks Etherscan, where she sees the amount as 50,000,000,000,000,000 wei and the gas price as 25 gwei. Because she understands the unit system, she can verify that everything matches her expectations.
This scenario illustrates how unit conversions happen automatically in wallets but understanding them helps you verify and trust the process.
Many people misunderstand cryptocurrency units, which can lead to confusion, errors, and even financial loss. Below are the most frequent misconceptions.
Not true. Ethereum and ERC-20 tokens often use 18 decimal places. Cardano uses 6. Always check the specific network.
No — a coin has its own blockchain, a token lives on another chain. This distinction affects security, fees, and functionality.
Only for Bitcoin. Other cryptocurrencies have their own smallest units with different names and values (wei, lovelace, etc.).
While the total cost is ultimately in ETH, gas is priced in gwei. Thinking only in ETH can obscure the actual fee structure.
Most wallets display amounts in the base unit by default, but some allow you to switch to satoshis or wei. Check your settings.
While many ERC-20 tokens use 18 decimals, some use fewer (e.g., USDC uses 6). Always verify the token’s specification.
Cryptocurrency transactions are generally irreversible. Sending funds to the wrong address or using the wrong denomination can result in permanent loss of assets. Always double-check the unit you are using and the amount you are sending.
This guide is educational and informational only. It does not constitute financial, legal, tax, or investment advice. You are responsible for your own transactions and decisions.
Unit names, decimal places, and network rules are subject to change with protocol upgrades. Always verify the current specifications of any cryptocurrency you use by consulting its official documentation or trusted sources.
Do not rely solely on third-party wallets or exchanges to handle unit conversions correctly. Understand the underlying system so you can independently verify your transactions.