A Satoshi is the smallest fraction of a Bitcoin that can currently be sent: 0.00000001 BTC. In the future, the protocol may be updated to allow further subdivisions should it be needed.
Examples of units
- 1 BTC = 100,000,000 Satoshis
- 1 BTC = 1000 mBTC (millibitcoin)
- 1 mBTC = 100,000 Satoshis
- 1 μBTC (microbitcoin) = 100 Satoshis