# This is how we know there’s only 21 Million Bitcoin

News anchor: 21 million

Jamie Dimon: Yeah really? How do you know it's gonna stop at 21 million

# Why don’t we take a look at the math?

Bitcoin's Supply Formula

Let me start by explaining this in an easier way

We are gonna multiply the number of blocks (210,000) by the number of coins each new block should print (50) which itself, will be divided by 2 which will be to the power of n, n being the halving we are at. So if we know that 2⁰=1, 2¹=2, 2²=4, and so on, we could conclude that 50/2⁰ = 50/1 = 50, 50/2¹ = 50/2 = 25, and so on, which all on itself means that at no halving we have 210,000 blocks adding 50 Bitcoin to the supply and at the first halving we have 210K new blocks adding 25 and so on.

So, let's do this manually

We are gonna start at 0 halvings

210,000 (50 / 2⁰) = 10,500,000*

Supply so far= 10,500,000

As you can see, we already have the first half of the whole supply, may we reach 21M soon?

Lets see, why don't we add the first halving to the supply?

210,000 (50 / 2¹) = 5,250,000*

Supply so far= 15,750,000 [which is the result of: 10,500,000 + 5,250,000]

Wait, this is not the same, this is half of what we initially got, what if we add another halving to the supply? We might get closer

2100,00 * (50 / 2²) = 2,625,000

Supply so far= 18,375,000 [15,750,000+2,625,000]

Ok, so we are getting closer, but at the same time we can't reach the goal, we have in Bitcoin's supply an example of the Zeno's Paradox where whenever you get to the half of a goal you can only move the half of the remaining distance.

After halving 32 we will arrive at a supply of 20,999,999.9769 Bitcoin, not 21M as we were promised but pretty close, we could continue doing this until the 32nd halving (the last one), but then this post would be too long, so here's a simple Bitcoin Supply Calculator for you to use.

# Now that we have the math all figured out, let's check the code

I won't enter too much into details here because I've never been that good with code, but I'll do my best to explain this as humanly as I can.

Block of code enforcing 50/2ⁱ

``````CAmount nSubsidy = 50 * COIN;
``````

What this line does is multiplying the number of the parameter COIN by 50, COIN being a binary representation of 100,000,000 which is number of Sats, the smallest unit the Bitcoin Network recognizes and the smallest divisible unit of a Bitcoin, being this number in binary: 100101010000001011111001000000000.

``````nSubsidy >>= halvings;
``````

This line is a “bitwise right shift” all it does is an arithmetic shift to the right by one bit, or simply put, divides by two in binary.

What this does is taking the number 100101010000001011111001000000000 and remove the last number of bits, being the numbers of bits, the same number of the halving we are at the moment, for this example imagine you have a dot at the end of the number and everything that moves after said dot is removed.

If nSubsidy is 0 our binary number stays the same

100101010000001011111001000000000 = 5,000,000,000 units of COIN

If nSubsidy is 1, we move one bit to the right, we remove the last bit by moving the whole number one space to the right, the last 0 being now after the dot and the rest of the number before it.

10010101000000101111100100000000 (you can count the 0 if you want)= 2,500,000,000 units of COIN

If nSubsidy is 3, which is the halving we are at at the time of writing then we move 3 bits

100101010000001011111001000000 = 625,000,000 units of COINThis all the way to 32 where we end up we only 1 bit, and after that comes nothing before the hypothetical dot.

``````if (halvings >=64) return 0;
``````

Is a bug fix, the wont be 64 halvings, it just ensures that if for any reason we ever go above 64 halvings the block subsidy forces itself to 0.

Block of code enforcing an interval of 210K blocks for every reduction of the subsidy

``````consensus.nSubsidyHalvingInterval = 210000;
``````

This line simply ensures the halving happens every 210,000 blocks.

If you want a more detailed explanation you could check Unchained Capital's post about it.

But they can update the code to remove the limit

There's a whole book on how a group of people tried to double the size of the blocks every two years and they couldn't, all they did was fork the network and now it's being delisted by one of the biggest exchanges for the lack of users. Nobody with at least two fingers of forehead will move to a version of Bitcoin where inflation is re-introduced when we all know the consequences of inflation.

Original post on Substack ⚡

### 50 thoughts on “This is how we know there’s only 21 Million Bitcoin”

1. !lntip 1337

2. !lntip 500

It also takes the precision loss into account (1 satoshi being the smallest unit and fractions being truncated to the lower whole number due to it being an integer and not a decimal).

It won’t be 21 Million satoshi due to the precision loss. 20’999’999.9769 BTC is the theoretical maximum. But even that is not possible anymore as miners forfeit some of the subsidy. For example this one that forfeited the entire 12.5 BTC subsidy of the block it mined.

4. To me, the thing about the halving is it’s in the public domain. That is, you can go look at the blockchain to see it’s actually happening and that’s what counts. Don’t trust, verify. No need to look at the code.

5. Jamie Demon’s comments will age like milk.

He is an evil fraudster and has some karma coming to him.

Great post!

!lntip 1000

6. These are the kind of posts that this sub needs more of.

7. Damn dude. This is front page reddit material. Good work!!! Mods, add to sidebar!

8. It will only be 21 million if everyone uses self custody. If people keep holding at a CEX, then its whatever they want it to be.

9. Nice but when a number has more than 3 digits, please use commas to make your numbers readable. 21,000,000 is easier read than 2100000.

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You probably didn’t even realize that the second number I wrote was only 2,100,000. That’s because there were no commas.

10. Why does it matter if there’s 21mil coins when scammers like SBF sell coins that dont exist. You realize if that didnt happen btc would’ve hit 100k?

11. !lntip 500

12. Post saved, top stuff.

13. who needs an entire bitcoin is the real question

14. I don’t understand a word but what a great response to sore looser JD

15. I love the post, but that wouldn’t be my argument (although you did mention this at the end of your post!). The formula is just code, and it can be changed any time, but thankfully not by the ‘CEO’ of Bitcoin. There are about 15,000 bitcoin nodes, and one of them is mine. If a majority of node operators were to decide that it was a good idea to increase the supply, it could be done. Of course, it would be against the interest of anyone holding Bitcoin, and all the new Bitcoin would go to the miners. The supply can’t increase unless network participants vote against their own interests, which is a pretty strong incentive to keep the limit as-is.

16. Jamie’s butthurt because he got in at \$60k/coin.

17. Brilliant explanation!

18. It’s all fun and games until the code encounters a value overflow and prints 180 billion bitcoins out of thin air … again. It bothers me that Satoshi wrote some insanely solid code … but didn’t bother to enforce state checks before and after a transaction. So if coins are mistakenly generated during a transaction, the network doesn’t know or care. A human operator has to visually monitor and catch that.

I get the appeal of “code is law”. It’s impartial and can’t be corrupted by greed. But ask any dev and they’ll tell you there’s no such thing as perfect code and it’s simply a matter of time before it finds another edge case failure.

19. Ohh I don’t think so

20. Great post, with references to Bitcoin source code. Don’t see this very often on this subreddit

!lntip 5000

21. In the image atop of the post should it not say 64 instead of 32? Since the code mentions the subsidy to be exactly 0 at 64 and above halvings.

22. Who says that math isn’t gorgeous!! Jamie is sh**ting outside the toilet.

Awesome explanation, thank you!

23. https://i.imgur.com/lnt7NEt.jpg

24. You dropped this. 👑

!lntip 2500

25. I would’ve just said it’s set in the code

26. Well, Jamie clearly has a secret stack of his own. JP Morgan released a paper about Bitcoin to their Preferred Client list.

27. !lntip 500

28. Actual quality post. Nice.

29. Nice Post OP!!! This is great!!

30. Technically you don’t know, right? If the consensus of nodes decided that more could be made, then more could be made. I suppose you’d call that a fork, but we’ve forked before and still called it Bitcoin.

31. Honest question, is anyone worried about the divisibility of BTC? And the context of a “coin” being swapped for a “sat” since sats are the unit most commonly transacted in? A system built on 2.1 quadrillion sats is better than what we have today but wanted to see if anyone has thought of the impacts of an economy trying to find price equilibrium on goods/services in that new system. Cheers.

32. Great break down!

33. > There’s a whole book on how a group of people tried to double the size of the blocks every two years and they couldn’t, all they did was fork the network and now it’s being delisted by one of the biggest exchanges for the lack of users. Nobody with at least two fingers of forehead will move to a version of Bitcoin where inflation is re-introduced when we all know the consequences of inflation.

Doubling the block size wouldn’t have changed the block reward, not sure how this is relevant to your post

34. This retard also said a picture of Satoshi laughing can pop up when btc has finally mined all 21mil.

It’s open source, dumbass. If there was a .jpg of Satoshi anyone would see it in the source code.

How these billionaires talk so smugly about things they don’t even have the slightest comprehension of is incredible. Unfortunately people who have not done any research may actually believe this crap.

35. Jaime maybe wrong about a lot of thing. When you’re in a high level influential position, people will always look at your faults before they consider your qualities. I think what he is really eluding to is that the crypto space is currently built upon a foundation of crumbling trust. Not that fiat is better but at least you can rely on the military dominance should the USD start to lose favor globally. This isn’t about a better currency system, this is about keeping the US as the dominant player in the game. It’s a game of fear and power. The US is the leading power because we have established a peaceful diplomatic way to bring order to the world. If the US slips and becomes 2 or 3 to china or Russia or even Bitcoin, there will be hell to pay domestically, as well as globally.

36. Solid my guy. Bitcoin is literally just math and physics

!lntip 2000

37. But have you tried ctrl + C, then ctrl + V?

38. Yes.

39. !lntip 1309

40. Jamie Dimon is smarter than me. But I guarantee he doesn’t understand this post or any of the math. Just like me. Yet that prick makes a killing.

41. These are the posts I want to read on this sub, thank you OP. I’m so tired of the horrible cookie cutter memes/posts that are just garbage that probably came from a bot

42. Classic. It’s ok no one at JP Morgan understands that (im an ex investment banker). They’re good at:

• making PowerPoint presentations;
• calculating net present values on some made up assumptions;
• convincing private clients (assuming you’re not in corporate side) to invest their millions into Lehman bonds.

But hey that’s why they bust their chips from 8am to 11pm for less than \$1m pa generally. Could hardly afford a nice place in Toronto or Singapore. Not very smart people who somehow think theyre smart

43. Beautiful 🤩

44. Quick mafs

45. !lntip 1000

46. Even in the worst case scenario is Satoshi came back to publish a bitcoin core update that would allow for more than 21million, no node would update their client lol.

47. And that is why Achilles never caught that Damn turtle!

48. Somebody share this with that old F Jamie Dimon! He has never used crypto, traded it, read the code or white paper, yet he has a clue what it is! 🤦‍♂️. This is the same guy that is offering .89% to his customers to hold their cash while he gains 6,7,8,9,10% on said cash by lending it to other customers or just buying T Bills. 🤦‍♂️😡🥴

49. Bitcoin price on the day this thread was made is \$22601.36. This was posted as a reference point to any future thread readers. Upvote if useful!

50. I wouldn’t trust Dimon any farther than I could toss the fuckwad. He’s been spreading FUD for years while buying all the Bitcoin he can. He’s another Wallstreet shitheel that is scared to death of crypto. People like him cannot pull their shifty shit with a blockchain or decentralization. Fuck em’ and feed em’ beans!