Sat

A sat is the smallest unit into which bitcoin can be divided on-chain, equal to one hundred-millionth of a single coin (0.00000001 BTC). Because the Bitcoin protocol tracks balances in whole satoshis rather than fractional coins, the fixed 21 million bitcoin supply cap actually represents about 2.1 quadrillion individual sats, giving the network far more usable granularity as the price of a whole coin rises.

The name honors Satoshi Nakamoto, Bitcoin's pseudonymous creator, though it does not appear in the original 2008 whitepaper. Early forum users coined the shorthand around 2010 and 2011 as a practical way to talk about tiny fractions of a coin, and the community adopted "satoshi" and its abbreviation "sat" soon after.

Sats show up throughout everyday Bitcoin use. Wallets and block explorers quote transaction fees in satoshis per virtual byte, and the Lightning Network settles most payments in sats, or even fractions of a sat, since amounts are typically too small to express conveniently in whole BTC. The unit also underpins Bitcoin's inscription system, where individual, sequentially numbered satoshis can carry embedded data or images.

Beyond its technical role, "sat" carries cultural weight in Bitcoin communities. "Stacking sats" describes the habit of buying small amounts of bitcoin on a regular schedule, a dollar-cost averaging approach that reframes an expensive asset as something anyone can accumulate gradually, one purchase at a time.