Bitcoin

Decentralized digital cryptocurrency BitcoinCommonly used logo of bitcoinDenominationsPluralbitcoinsSymbol₿(Unicode: U+20BF ₿ BITCOIN SIGN)CodeBTCPrecision10−8Subunits 1⁄1000millibitcoin 1⁄1000000microbitcoin 1⁄100000000satoshiDevelopmentOriginal authorSatoshi NakamotoWhite paper"Bitcoin: A Peer-to-Peer Electronic Cash System"ImplementationBitcoin CoreInitial release0.1.0 / 9 January 2009 (17 years ago) (2009-01-09)Latest release31.1.0 / 7 July 2026 (39 days ago) (2026-07-07)Code repositorygithub.com/bitcoin/bitcoinDevelopment statusActiveWritten inC++Source modelFree and open-source softwareLicenseMIT LicenseLedgerLedger start3 January 2009 (17 years ago) (2009-01-03)Timestamping schemeProof of work (partial hash inversion)Hash functionSHA-256 (two rounds)Issuance scheduleDecentralized (block reward)Initially ₿50 per block, halved every 210,000 blocksBlock reward₿3.125 (as of 2026[update])Block time10 minutesCirculating supply₿20,057,778 (as of 12 June 2026[update])Supply limit₿21,000,000ValuationExchange rateFloatingWebsiteWebsitebitcoin.org Bitcoin (abbreviation: BTC; sign: ₿) is the first decentralized cryptocurrency. Based on a free-market ideology, bitco