Satoshi: the smallest Bitcoin unit

From Whole Bitcoin to Satoshis

A satoshi is the smallest divisible unit of Bitcoin. One BTC equals 100,000,000 satoshis—often shortened to sats—meaning each satoshi is 0.00000001 BTC. The unit takes its name from Satoshi Nakamoto, the pseudonymous creator who published the Bitcoin white paper in 2008 and mined the first block in January 2009.

Bitcoin is divisible to eight decimal places for a practical reason. If a single BTC eventually trades at six or seven figures, daily transactions still need to settle in small, intuitive amounts. Sats make microtransactions feasible: paying a fraction of a cent for an API call, tipping a content creator, or splitting a coffee bill only requires a handful of satoshis rather than a tiny BTC fraction.

Most exchanges and wallets display balances in BTC by default, but many let you switch to a sat-denominated view. The Lightning Network, which moves Bitcoin payments off-chain for instant settlement, prices almost everything in sats. Understanding the unit removes a common source of confusion when reading fees, on-chain transfers, and price quotes.