Bitcoin's monetary policy is written into the software and known in advance: there will never be more than 21 million bitcoin.
How new coins appear
The only way new bitcoin is created is through the block reward paid to miners. In 2009 it was 50 BTC per block. Every 210,000 blocks — roughly every four years — that subsidy is cut in half. This is the halving.
- 2009: 50 BTC
- 2012: 25 BTC
- 2016: 12.5 BTC
- 2020: 6.25 BTC
- 2024 (April): 3.125 BTC
- ~2028 (block 1,050,000): 1.5625 BTC
As of October 2026 (block ~972,800), just over 20.1 million bitcoin have been mined. Because of the halvings, the last fraction of a satoshi will be issued around the year 2140.
Why it matters
Most currencies can be issued at will by a central bank. Bitcoin's issuance is predictable and declining, which is why some call it "digital gold". Changing the cap would require nearly all nodes to adopt new rules — something users have strong incentives to reject.
What happens after 2140?
Miners will then earn only transaction fees. Whether fees will be enough to fund strong security is one of Bitcoin's long-term open questions.
Also note: coins whose keys are lost are effectively out of circulation forever, so the usable supply is somewhat lower than 21 million.