page_title: Bitcoin
section_title: Supply
hierarchical_section_title: Bitcoin / Design / Mining / Supply
context_page_description: Bitcoin is a cryptocurrency invented in 2008 by an unknown person or group of people using the name Satoshi Nakamoto and started in 2009 when its implementation was released as open-source software.
  It is a decentralized digital currency without a central bank or single administrator that can be sent from user to user on the peer-to-peer bitcoin network without the need for intermediaries. Transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain. Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services. Research produced by University of Cambridge estimates that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin.
  Bitcoin has been praised and criticized. Critics noted its use in illegal transactions, the large amount of electricity used by miners, price volatility, and thefts from exchanges. Some economists, including several Nobel laureates, have characterized it as a speculative bubble.
context_section_description: The successful miner finding the new block is allowed by the rest of the network to reward themselves with newly created bitcoins and transaction fees. As of 11 May 2020, the reward amounted to 6.25 newly created bitcoins per block added to the blockchain, plus any transaction fees from payments processed by the block. To claim the reward, a special transaction called a coinbase is included with the processed payments. All bitcoins in existence have been created in such coinbase transactions. The bitcoin protocol specifies that the reward for adding a block will be halved every 210,000 blocks (approximately every four years). Eventually, the reward will decrease to zero, and the limit of 21 million bitcoins will be reached c. 2140; the record keeping will then be rewarded solely by transaction fees.
  In other words, Nakamoto set a monetary policy based on artificial scarcity at bitcoin's inception that the total number of bitcoins could never exceed 21 million. New bitcoins are created roughly every ten minutes and the rate at which they are generated drops by half about every four years until all will be in circulation.
caption: Total bitcoins in circulation.[89]