Definition
A satoshi, often shortened to sat, is 0.00000001 BTC. There are 100 million satoshis in one bitcoin. The unit is named after Satoshi Nakamoto, the pseudonymous creator of Bitcoin. It is a denomination of bitcoin, not a separate token with its own issuer or independent market price.
Working with Satoshis
Small amounts are often easier to read in sats than as long decimal fractions of BTC. For example, 50,000 sats equals 0.0005 BTC. Its fiat value depends on the prevailing BTC exchange rate. Bitcoin transaction fee rates are commonly quoted in satoshis per virtual byte, which measures the price of transaction space rather than a percentage of the amount transferred.
Key Considerations
Always distinguish an amount in sats from a fee rate in sat/vB. A total fee depends on both the rate and the transaction’s virtual size. Some systems, including Lightning payment accounting, can express sub-satoshi units internally, but Bitcoin’s base-layer transaction outputs are denominated in whole satoshis. Small units do not remove network fees or price volatility.