1.3Lesson 3 of 8
How many bitcoin there are
This lesson answers
- How many bitcoin are there?
- How many bitcoin are left to mine?
- What is the halving, and when is the next one?
- Can more than 21 million bitcoin ever be made?
There will never be more than 21 million bitcoin. The rules set how much new bitcoin each block may create, and cut that amount in half every 210,000 blocks, about every four years. This is called the halving.
- Created so far
- …
- Share of 21 million
- …
- Still to come
- …over the next 110 or so years
- New per block now
- …
- Next halving
- …block number
- Blocks to go
- …
At about ten minutes a block, the next halving lands around …. After it, each block creates ….
See it on satoshis.watch →The schedule
| Blocks | Years | New bitcoin per block |
|---|---|---|
| 0 to 209,999 | 2009 to 2012 | 50 |
| 210,000 to 419,999 | 2012 to 2016 | 25 |
| 420,000 to 629,999 | 2016 to 2020 | 12.5 |
| 630,000 to 839,999 | 2020 to 2024 | 6.25 |
| 840,000 to 1,049,999 | 2024 to about 2028 | 3.125 (now) |
| 1,050,000 onward | from about 2028 | 1.5625, then halving again |
The halvings go on until the amount rounds down to nothing, around the year 2140. Because each step adds half as much as the one before, the total ends just under 21 million and never passes it. Every computer running Bitcoin checks this: a block that pays its miner more than allowed is rejected.
Why the real number is a little lower
The count above follows the rules. Some of those coins can never move: the 50 bitcoin of the very first block cannot be spent, some early miners claimed less than they were allowed, and some coins were sent to addresses that nobody is known to control. Many more are simply lost because their keys are gone; see lost and sleeping coins.
- Bitcoin sent there
- …
- Payments received
- …
The Bitcoin Eater address spells out its own warning. Nobody is known to hold its key, so bitcoin sent there is treated as destroyed. It still counts in the total above.
See it on satoshis.watch →Check yourself
Practice, not a test. Think of your answer first, then reveal it.
1What happens at a halving?Reveal
The new bitcoin each block creates is cut in half. Coins that already exist don't change.
2Can there ever be more than 21 million bitcoin?Reveal
Not under the rules every Bitcoin computer checks. A block that created more than allowed would be rejected by all of them.
3Why can fewer coins be spent than have been created?Reveal
Some can never move, such as the first block's reward and coins sent to burn addresses, and many others are lost.
Sources
- Bitcoin Core, GetBlockSubsidy: the rule that sets each block's new bitcoin.
- Live figures are worked out from the newest block's number, read from a Bitcoin node.