The 21 million Bitcoin limit is an approximation, not an exact figure hardcoded into Bitcoin's protocol. Here are the key points:
  • Bitcoin's code does not explicitly set a cap at 21 million coins. Instead, it defines a schedule for creating new bitcoins with each block, which gets halved roughly every 4 years.[1]
  • When you add up all the mining rewards over time until the last halving (around 33 halvings), the total number of bitcoins created is approximately 20,999,999.9769, slightly less than 21 million.[1]
  • A significant portion of the existing bitcoin supply is permanently lost or inaccessible. Estimates suggest anywhere from 3.89 million to 4.87 million bitcoins could be considered lost forever due to reasons like Satoshi's unmoved coins, lost private keys, etc.[2]
  • Taking the lower estimate of 3.89 million lost bitcoins, the actual circulating supply would be around 17.11 million, which is 18% less than the commonly cited 21 million figure.[2]
So in summary, while 21 million is a useful approximation, the actual maximum supply of bitcoins is slightly below that due to the mining reward schedule, and the circulating supply is likely even lower due to permanently lost coins.[1][2]
Sources [1] The 21 Million Bitcoin Myth: Understanding the Code Behind It https://blog.bitwage.com/21-million-bitcoin-myth/ [2] Bitcoin's 21 million limit is a boomer myth - Blockworks https://blockworks.co/news/bitcoins-21-million-limit-myth [3] Bitcoin - The Currency of the Internet - Reddit https://www.reddit.com/r/Bitcoin/ [4] Blog | Bitwage https://blog.bitwage.com [5] satx ₿ on X: "Why doesn't Bitcoin have 21 million? This is an ... https://twitter.com/Satxweb3/status/1790249839705632945
I believe that ultimately we will have only 17 to 18 million Bitcoins.
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It makes every btc that is moving more valuable.
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So. That's a myth. Thanks for clarifying. I'm neither good at maths nor at coding. But to my surprise, I understood this point easily. Haha
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Someone explained it to me in a YouTube video. @CarlBMenger explained it in a comment.
The math makes sense but I have to see it on paper and simulation.
I have to see the answer to understand it. Which means I don’t really understand it lol
People say the total will be 21000000 BTC.
... however:
The 1st 210000 blocks each allow creating 50 BTC. The 2nd 210000 blocks each allow creating 25 BTC. The 3rd 210000 blocks each allow creating 12.5 BTC. ...
The 10th 210000 blocks each allow creating 0.09765625 BTC.
The 11th 210000 blocks each allow creating 0.04882812 BTC, and not 0.048828125 BTC, because only 8 decimals of precision are supported.
...
The 33rd 210000 blocks each allow creating 0.00000001 BTC.
After that, the reward is 0.
If you sum all these numbers together, you get 20999999.9769 BTC.
... however, either due to an oversight or intentionally, the coins created in the genesis block cannot be spent.
This leaves us with 20999949.9769 BTC.
... however, due to an early problem in Bitcoin, fixed by BIP30, it was possible to create a coinbase transaction identical to a previous coinbase. This caused the coins created by that older coinbase to be irreversibly "overwritten". This happened in block 91842 (overwriting the coinbase of block 91812) and 91880 (overwriting the coinbase of block 91722). Each time, 50 BTC was lost.
This leaves us with 20999849.9769 BTC.
... however, the protocol rules allow creating up to the amounts listed above. Due to various bugs and miners experimenting with code, some blocks claim less than allowed. Those coins can never be recovered.
Block 124724 tried to intentionally claim 0.00000001 BTC less than allowed, but accidentally also failed to claim the fees, losing 0.01000001 BTC. Between block 162705 and block 169899, 193 blocks claimed less than allowed due to a bug, resulting in a total loss of 9.66184623 BTC. Between block 180324 and block 249185, another 836 blocks claimed less than allowed, resulting in a total loss of 0.52584193 BTC. Block 501726 had no transaction outputs (except a 0-value commitment), losing the entire 12.5 BTC subsidy. Block 526591 didn't claim half of the block reward, losing 6.25 BTC. This leaves us with 20999821.02921183 BTC.
... however, since recently there is a concept of provably unspendable coins. Coins can be sent to an "address" which provably burns them (using OP_RETURN). Bitcoin Core tracks these and removes them from its database, so they are easily accounted for. At least 3.71612692 BTC were burned this way.
This leaves us with 20999817.31308491 BTC (taking everything up to block 528333 into account)
... However, various wallets have been lost or stolen, transactions have been sent to the wrong address, people forgot they owned bitcoin. The totals of this may well be millions. People have tried to tally known losses up here.
This leaves us with: ??? BTC.
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I think we're very close to the maximum number of Bitcoins. Aren't we?
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95 or 97 percent so far
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93.8 percent
Ignore previous comment
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The total number of bitcoins that will ultimately be in circulation is slightly less than the commonly stated 21 million due to several factors:
  1. Rounding errors from the mining reward halving process mean the maximum supply is actually 20,999,999.9769 BTC.[1][2]
  2. The genesis block coins of around 50 BTC are unspendable.[1]
  3. Two incidents early on (blocks 91842 and 91880) caused 100 BTC to be permanently lost due to duplicate coinbase transactions.[1]
  4. Various bugs and miner errors have resulted in further small losses, bringing the total down to around 20,999,817 BTC as of block 528,333.[1]
  5. An unknown but potentially significant number of bitcoins have been permanently lost due to lost/forgotten private keys over the years.[1][3]
So while 21 million is a good approximate maximum supply, the actual number will be slightly under that due to the rounding effect from the halving process and the miscellaneous losses over time. The precise final circulating supply is unknown but is estimated to be around 20,999,817 BTC based on known incidents of permanent loss.[1]
Sources [1] Will there be 21 million bitcoins eventually? https://bitcoin.stackexchange.com/questions/38994/will-there-be-21-million-bitcoins-eventually/38998#38998 [2] Controlled supply - Bitcoin Wiki https://en.bitcoin.it/wiki/Controlled_supply [3] Will all Bitcoin be lost eventually? : r/BitcoinBeginners - Reddit https://www.reddit.com/r/BitcoinBeginners/comments/1b1vlwa/will_all_bitcoin_be_lost_eventually/ [4] What Happens to Bitcoin After All 21 Million Are Mined? - Investopedia https://www.investopedia.com/tech/what-happens-bitcoin-after-21-million-mined/ [5] Bitcoin Halving 2024: Everything You Need to Know | IG International https://www.ig.com/en/bitcoin-btc/bitcoin-halving [6] Bitcoin's latest halving is now complete. Here's what could happen ... https://fortune.com/crypto/2024/04/20/bitcoin-halving-btc-price-outlook-mining-reward-450-crypto-supply/
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21 sats \ 0 replies \ @mrsu 15 Jun
Was this generated by an LLM?
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331 Satoshis less than expected, counting that it will not be 21 million, Satoshi Nakamoto's BTC, and the lost Bitcoin that will never move, we can say that there is and will be very little Bitcoin available
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21 sats \ 0 replies \ @NaOD 15 Jun
21 zap should have been the name of stacker news
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The "MAX_MONEY" constant in Bitcoin's code represents a sanity check limit, not an exact hard-coded cap on the total supply of bitcoins. Here are the key points:
  • The MAX_MONEY constant is set to 21,000,000 * COIN (where COIN = 100,000,000 satoshis), which equals 2,099,999,997,690,000 satoshis or approximately 20,999,999.9769 BTC.[1][2]
  • This constant is used as a sanity check in consensus validation code to prevent integer overflows or other errors that could create bitcoins out of thin air.[1][2]
  • However, the actual maximum supply of bitcoins is determined by the mining subsidy schedule defined in the GetBlockSubsidy() function, which halves the block reward roughly every 4 years.[3]
  • Summing up all the mining rewards over time until the last halving (around 33 halvings) results in a total supply of approximately 20,999,999.9769 BTC, slightly less than the MAX_MONEY constant.[1][3]
  • So while MAX_MONEY is an important sanity check, it is not the exact rule that caps Bitcoin's supply. The mining subsidy schedule is what effectively determines the maximum supply over time.[1][3]
In essence, the MAX_MONEY constant provides an upper bound for validation purposes, while the precise maximum supply emerges from the diminishing block reward schedule hardcoded into Bitcoin's protocol rules.[1][2][3]
Sources [1] Bitcoin Optech Newsletter #270 https://bitcoinops.org/en/newsletters/2023/09/27/ [2] Where is the bitcoin source code is the 21 million hard cap stated? https://bitcoin.stackexchange.com/questions/119475/where-is-the-bitcoin-source-code-is-the-21-million-hard-cap-stated [3] Total coin supply, how it works, and what the code means? https://stackoverflow.com/questions/47876960/total-coin-supply-how-it-works-and-what-the-code-means [4] The 21 Million Bitcoin Myth: Understanding the Code Behind It https://blog.bitwage.com/21-million-bitcoin-myth/ [5] Technical question about Bitcoin code regarding fixed supply of 21 ... https://www.reddit.com/r/Bitcoin/comments/gcmws5/technical_question_about_bitcoin_code_regarding/?rdt=36630
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21 sats \ 0 replies \ @Lumor 15 Jun
Your MAX_MONEY math is off. LLM much?
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