Bitcoin Prevailing bitcoin logo Prevailing bitcoin logo Denominations Plural bitcoins Symbol ₿[a] Ticker symbol BTC, XBT[b] Subunits  ​1⁄1000 millibitcoin  ​1⁄100000000 satoshi[2] Coins Unspent outputs of transactions (in multiples of a satoshi)[3]:ch. 5 Development Original author(s) Satoshi Nakamoto White paper "Bitcoin: A Peer-to-Peer Electronic Cash System"[5] Implementation(s) Bitcoin Core Initial release 0.1.0 / 9 January 2009 (9 years ago) Latest release 0.16.2 / 29 July 2018 (9 days ago)[4] Website bitcoin.org Ledger Ledger start 3 January 2009 (9 years ago) Timestamping scheme Proof-of-work (partial hash inversion) Hash function SHA-256 Issuance Decentralized (block reward)[7][8] Block reward ₿12.5[c] Block time 10 minutes Block explorer www.blockchain.com Circulating supply ₿16,858,762 (as of 11 February 2018) Supply limit ₿21,000,000 [6] The symbol was encoded in Unicode version 10.0 at position U+20BF ₿ BITCOIN SIGN in the Currency Symbols block

Bitcoin