What is Satoshi?

A satoshi (sometimes abbreviated as “sat”) is the smallest divisible unit of Bitcoin. One satoshi equals 0.00000001 BTC — that is, one hundred millionth of a Bitcoin. The unit is named after Bitcoin’s pseudonymous creator, Satoshi Nakamoto.

Why satoshis matter

As Bitcoin’s price has risen, transacting in whole bitcoin has become impractical for most everyday purchases. At a Bitcoin price of $60,000, one cent is roughly 167 satoshis. Pricing small goods and services in satoshis is a much more intuitive way to think about micro-transactions than dealing with long decimal strings of BTC.

This is especially true on the Lightning Network, where the standard unit of account is satoshis rather than bitcoin. Lightning invoices, channel balances, and node routing fees are all denominated in sats.

How to use satoshis

Most wallets let you switch the display unit between BTC and sats. Some Lightning-first wallets (Phoenix, Wallet of Satoshi) default to displaying balances and amounts in sats. When paying a Lightning invoice, you can usually specify the amount in sats directly.

Other unit names

Bitcoin has several traditional unit names, most rarely used in practice today:

• 1 BTC = 1 bitcoin
• 1 mBTC (millibitcoin) = 0.001 BTC = 100,000 sats
• 1 μBTC (microbitcoin, “bit”) = 0.000001 BTC = 100 sats
• 1 satoshi = 0.00000001 BTC

Outside of Bitcoin, other cryptocurrencies have their own smallest units. Ethereum’s smallest unit is wei (1 ETH = 10^18 wei), and Solana’s is lamport.