Satoshis, often represented as “sat” or “sats” for short, are the smallest unit of measurement for Bitcoin (BTC). A satoshi is equal to 0.00000001 BTC and is named after the pseudonym of the creator of Bitcoin, Satoshi Nakamoto.
For example, if the price of Bitcoin is $50,000, then one satoshi would be worth 0.00000001 * $50,000 = $0.005.
Satoshis are used to express small amounts of Bitcoin, such as transaction fees, and can be more convenient than using fractions of a Bitcoin. It is also used to express the profit/loss in terms of percentage, when trading with a small amount of Bitcoin, it is more convenient to express the profit/loss in terms of satoshis.
In general, it’s common to see prices and quantities of Bitcoin measured in satoshis, rather than in fractions of a Bitcoin, making it a unit of denomination used in trading and in everyday conversation about Bitcoin.
