21 million supply cap
From Satoshipedia, the Satoshi Mail encyclopedia
Bitcoin's supply is capped at 21 million coins, and the block reward halves every 210,000 blocks.[1] Satoshi set out the schedule in the v0.1 release notes, “with the amount cut in half every 4 years” (release notes), and repeated it in the 0.3 announcement: “Bitcoin's total circulation is limited to 21 million coins.” (the announcement).
When users worried that so few coins could not serve the world, he pointed to divisibility: “Eventually at most only 21 million coins for 6.8 billion people in the world if it really gets huge. But don't worry, there are another 6 decimal places that aren't shown” (the post). See Satoshi (unit).
On lost coins he wrote: “Lost coins only make everyone else's coins worth slightly more. Think of it as a donation to everyone.” (the post).
When Mike Hearn asked in 2009 where “24 million coins” came from, Satoshi replied that “there's only going to be 21 million coins for the whole world” (the emails).
See also
References
- Bitcoin, Wikipedia (CC BY-SA 4.0). Retrieved 20 October 2026.
Primary sources
The messages and commits this article draws on, in Satoshi Mail and where they were first published.
- [bitcoin-list] Bitcoin v0.1 Alpha release notes, bitcoin-list (SourceForge), 12 January 2009. Original source
- [bitcoin-list] Bitcoin 0.3 released!, bitcoin-list (SourceForge), 6 July 2010. Original source
- How divisible are bitcoins and other market/economic questions, BitcoinTalk forum, 6 February 2010. Original source
- Dying bitcoins, BitcoinTalk forum, 21 June 2010. Original source
- Questions about BitCoin, Private email with Mike Hearn, 12 April 2009. Original source
Published by Tyler Howell for Satoshi Mail. Written with AI assistance from the sources listed above and checked against them. Last updated 22 October 2026. Spotted an error? Email itstylerhowell@gmail.com (how articles are made).
Categories: Economics