Why 21,000,000 Supply?

[BitcoinBlack]

I've read many of Satoshi's previous posts and writings, it's mind blowing how Satoshi was expecting bitcoin to come this far and he was prepared for it. Even in one of his posts he says he placed 8 decimals for upcoming decades... I've looked but couldn't find any info about what made him choose 21,000,000 as number of supply? Is there any logic/reason behind choosing that number? would love to know!

[1713284919]

1713284919

[1713284919]

1713284919

[BitcoinBlack]

I guess no one knows anything about that...

[Mometaskers]

I've read many of Satoshi's previous posts and writings, it's mind blowing how Satoshi was expecting bitcoin to come this far and he was prepared for it. Even in one of his posts he says he placed 8 decimals for upcoming decades... I've looked but couldn't find any info about what made him choose 21,000,000 as number of supply? Is there any logic/reason behind choosing that number? would love to know!

It seems to be just an arbitrary choice. He could have set any limit. I don't remember it being mentioned by anyone that he posted any reasons for it. It's just what he decided on, for reasons only he knows.

Personally I would have like it to be 42M.  

[BitcoinBlack]

I've read many of Satoshi's previous posts and writings, it's mind blowing how Satoshi was expecting bitcoin to come this far and he was prepared for it. Even in one of his posts he says he placed 8 decimals for upcoming decades... I've looked but couldn't find any info about what made him choose 21,000,000 as number of supply? Is there any logic/reason behind choosing that number? would love to know!

It seems to be just an arbitrary choice. He could have set any limit. I don't remember it being mentioned by anyone that he posted any reasons for it. It's just what he decided on, for reasons only he knows.

Personally I would have like it to be 42M.  

Haha yeah, thanks! I guess he just choose it.. I was thinking someone that smart has a reason to choose that number. In one of his posts he was talking about world population and bitcoin supply..  I think he wanted to create scarcity, clearly 21m is not enough for over 6 billion people

[randythered]

I've read many of Satoshi's previous posts and writings, it's mind blowing how Satoshi was expecting bitcoin to come this far and he was prepared for it. Even in one of his posts he says he placed 8 decimals for upcoming decades... I've looked but couldn't find any info about what made him choose 21,000,000 as number of supply? Is there any logic/reason behind choosing that number? would love to know!

It seems to be just an arbitrary choice. He could have set any limit. I don't remember it being mentioned by anyone that he posted any reasons for it. It's just what he decided on, for reasons only he knows.

Personally I would have like it to be 42M.  

Haha yeah, thanks! I guess he just choose it.. I was thinking someone that smart has a reason to choose that number. In one of his posts he was talking about world population and bitcoin supply..  I think he wanted to create scarcity, clearly 21m is not enough for over 6 billion people

Likewise I do not know of any reason, it seems a strange number to choose which makes me think that there must be some reason behind it. Perhaps it's just a lucky number of his or something as simple as that. But you'd think if he was just going to pick a value he'd have gone 10m or 100m or such.

[pereira4]

I've read many of Satoshi's previous posts and writings, it's mind blowing how Satoshi was expecting bitcoin to come this far and he was prepared for it. Even in one of his posts he says he placed 8 decimals for upcoming decades... I've looked but couldn't find any info about what made him choose 21,000,000 as number of supply? Is there any logic/reason behind choosing that number? would love to know!

It seems to be just an arbitrary choice. He could have set any limit. I don't remember it being mentioned by anyone that he posted any reasons for it. It's just what he decided on, for reasons only he knows.

Personally I would have like it to be 42M.  

Haha yeah, thanks! I guess he just choose it.. I was thinking someone that smart has a reason to choose that number. In one of his posts he was talking about world population and bitcoin supply..  I think he wanted to create scarcity, clearly 21m is not enough for over 6 billion people

Likewise I do not know of any reason, it seems a strange number to choose which makes me think that there must be some reason behind it. Perhaps it's just a lucky number of his or something as simple as that. But you'd think if he was just going to pick a value he'd have gone 10m or 100m or such.

There was actually a reason behind it that had to do with how bytes are divided or something like that, or maybe with the gold supply... I remember reading some theory about it, so it was not fully arbitrary, there was some thought put into it.

It's similar to the 1MB blocksize, it is what it is, but there is also thought put behind the number. Satoshi didn't simply roll a dice and choose these numbers.

[apvmoreira]

I think that his purpose was to create scarcity. When bitcoin mining became unsustainable, the value is going to raise like never before, and the coin itself will be seen has a good, not a exchange object, like normal coins.

When that time arrives, other coin(s) will take the role of bitcoin as the reference coin.

[Bobby park]

I think that his purpose was to create scarcity. When bitcoin mining became unsustainable, the value is going to raise like never before, and the coin itself will be seen has a good, not a exchange object, like normal coins.

When that time arrives, other coin(s) will take the role of bitcoin as the reference coin.

Like what happens now, bitcoin price unceasingly moves upward because the supply of bitcoin is much lower than other altcoins. When the demand goes high the supply goes down. When that happens price of bitcoin continuously goes up. Logically speaking, bitcoin calculated the amount of bitcoin that will circulate in the global economy. If the number of bitcoin is 21 million above do you think it will have value for now? Yes, it has but for sure it is not the same as today. If the number of bitcoin is less than 21 million, for sure that will lead to scarcity.

[gentlemand]

There was actually a reason behind it that had to do with how bytes are divided or something like that, or maybe with the gold supply... I remember reading some theory about it, so it was not fully arbitrary, there was some thought put into it.

It's similar to the 1MB blocksize, it is what it is, but there is also thought put behind the number. Satoshi didn't simply roll a dice and choose these numbers.

It's detailed here - https://bitcoinmagazine.com/articles/satoshis-genius-unexpected-ways-in-which-bitcoin-dodged-some-cryptographic-bullet-1382996984/

Quite stunning how much thought went into every possible aspect. That's why I think it was a group that did. A bunch of heads finds many more potential holes than one.

[eminemcookie]

There was actually a reason behind it that had to do with how bytes are divided or something like that, or maybe with the gold supply... I remember reading some theory about it, so it was not fully arbitrary, there was some thought put into it.

It's similar to the 1MB blocksize, it is what it is, but there is also thought put behind the number. Satoshi didn't simply roll a dice and choose these numbers.

It's detailed here - https://bitcoinmagazine.com/articles/satoshis-genius-unexpected-ways-in-which-bitcoin-dodged-some-cryptographic-bullet-1382996984/

Quite stunning how much thought went into every possible aspect. That's why I think it was a group that did. A bunch of heads finds many more potential holes than one.

So from what I can tell there's no particular reason that it's exactly 21m but there is a reason it's under a certain amount and that is with regard to how computers can process integers, interesting, still think there must be something behind 21, based on what I read it could have been 22m or any number close to it.

[snowyNNN]

I´m going with this:


1 X 3 X 7 = 21

[Hydrogen]

It's detailed here - https://bitcoinmagazine.com/articles/satoshis-genius-unexpected-ways-in-which-bitcoin-dodged-some-cryptographic-bullet-1382996984/

Quite stunning how much thought went into every possible aspect. That's why I think it was a group that did. A bunch of heads finds many more potential holes than one.

Excellent info. Thanks for posting that.

I still think David Kleiman who passed away in 2013, was Satoshi:

https://gizmodo.com/the-strange-life-and-death-of-dave-kleiman-a-computer-1747092460

I always thought that bitcoin's supply would be a number that was an exponent of 2 or devised to fit inside standardized variables, or some other unit of measure. It makes sense from an IT engineering perspective. I never knew that addresses were a hash of a public key though, rather than the public key itself. The part about elliptic curves is also very interesting although way over my head.

[BitcoinBlack]

There was actually a reason behind it that had to do with how bytes are divided or something like that, or maybe with the gold supply... I remember reading some theory about it, so it was not fully arbitrary, there was some thought put into it.

It's similar to the 1MB blocksize, it is what it is, but there is also thought put behind the number. Satoshi didn't simply roll a dice and choose these numbers.

It's detailed here - https://bitcoinmagazine.com/articles/satoshis-genius-unexpected-ways-in-which-bitcoin-dodged-some-cryptographic-bullet-1382996984/

Quite stunning how much thought went into every possible aspect. That's why I think it was a group that did. A bunch of heads finds many more potential holes than one.

Thanks for sharing! I Will definitely check that out. Indeed, it's really hard to believe all this was done by a person..

[Sahyadri]

There was actually a reason behind it that had to do with how bytes are divided or something like that, or maybe with the gold supply... I remember reading some theory about it, so it was not fully arbitrary, there was some thought put into it.

It's similar to the 1MB blocksize, it is what it is, but there is also thought put behind the number. Satoshi didn't simply roll a dice and choose these numbers.

It's detailed here - https://bitcoinmagazine.com/articles/satoshis-genius-unexpected-ways-in-which-bitcoin-dodged-some-cryptographic-bullet-1382996984/

Quite stunning how much thought went into every possible aspect. That's why I think it was a group that did. A bunch of heads finds many more potential holes than one.

That was really a good read. So 21 million limit is not just an arbitrary number. Satoshi was a mastermind and he wouldn't choose just a random number when he could potentially expect Bitcoin to workout the way it is now. As the article said, Satoshi chose this number based on mathematics as the largest integer that can be stored in a standard integer on a computer. I don't know whether this is true or not but then how would the other crypto currencies with larger supply than BTC would workout ?

[iamTom123]

I've read many of Satoshi's previous posts and writings, it's mind blowing how Satoshi was expecting bitcoin to come this far and he was prepared for it. Even in one of his posts he says he placed 8 decimals for upcoming decades... I've looked but couldn't find any info about what made him choose 21,000,000 as number of supply? Is there any logic/reason behind choosing that number? would love to know!

It seems to be just an arbitrary choice. He could have set any limit. I don't remember it being mentioned by anyone that he posted any reasons for it. It's just what he decided on, for reasons only he knows. Personally I would have like it to be 42M.  

I would not have any problem had it been set to have the maximum of 100 Million Bitcoin...that would have been much better though of course we don't really know as to why Satoshi Nakamoto decided to fixed the supply at 21 Million. I am sure he can provide an explanation for this but since it would be impossible for us to contact the gifted guy then we will just leave it at that...am sure we can read some speculations on why this is so but all of those are just speculations and can not be verified. Right now, we can see that this limited supply against the increasing demand is one of the biggest factors why the price or value of Bitcoin surging by leaps and bounds.

[TimtheYoutuber]

https://bitcoinmagazine.com/articles/satoshis-genius-unexpected-ways-in-which-bitcoin-dodged-some-cryptographic-bullet-1382996984/

Code:

"The 21 Million BTC limit

One somewhat controversial property of Bitcoin is its fixed currency supply. There are currently 25 BTC being generated every 10 minutes, and this amount cuts in half every four years. All in all, there will never be more than 21 million BTC in existence. On the other hand, each bitcoin can be split into 100 million pieces (called "satoshis"), so it will not become difficult to use Bitcoin if its value goes up the same way it would become problematic to trade with dollars if each penny was enough to buy a car. Thus, all in all, the total number of currency units that will ever exist stands at 2,100,000,000,000,000: 2.1 quadrillion, or about 250.899. In choosing this figure, Satoshi was much luckier, or wiser, than most people realize. First of all, the number is considerably less than 264 - 1, the largest integer that can be stored in a standard integer on a computer - go above that, and the integers wrap around to zero like an odometer.

Second, however, there is another, lower threshold that the total satoshi count manages to fall just below: the largest possible integer that can be exactly represented in floating point format. Integers are not the only kind of number that computers can store; to handle decimal numbers, computers use a format known as floating point representation. Floating point representation is essentially a binary version of scientific notation. For example, here are some values that you may be familiar with if you studied any physics:

    Mass of the Earth: 5.972 * 1024 kg
    Mass of the Sun: 1.989 * 1030 kg
    Speed of light: 2.998 * 108 m/s
    One lightyear: 9.460 * 1015 m
    Mass of a proton: 1.672 * 10-27 kg
    Planck length: 1.616 * 10-35 m

Notice how scientific notation allows you to express all of these values with reasonable accuracy despite their wildly varying scales. Floating point notation is essentially scientific notation in binary; when you store the number 9.625, your computer stores "1.001101 * 1011" (or rather, it stores 01000000 00100011 01000000 00000000 00000000 00000000 00000000 00000000, which is the same thing in high-precision serialized form). In this high-precision form, the "significand" (the part that's not the exponent) has 52 bits. What this means is that high-precision (more precisely, "double precision") floating point numbers are good enough to exactly store integers up to 253, but not higher - if you go higher, you start lopping off digits at the end. Bitcoin's 250.9 satoshis are, in exponential terms, just below this maximum. "

It is really interesting. 21m is a lot, but its small enough to allow bitcoin to reach $10k's+ which is very eye catching for a lot of people. So I am sure that played some sort of role.

[Rinsend]

I've read many of Satoshi's previous posts and writings, it's mind blowing how Satoshi was expecting bitcoin to come this far and he was prepared for it. Even in one of his posts he says he placed 8 decimals for upcoming decades... I've looked but couldn't find any info about what made him choose 21,000,000 as number of supply? Is there any logic/reason behind choosing that number? would love to know!

I firmly believe that the amount of 21,000.00 is made so that bitcoin has a limit.
because if bitcoin is not limited then bitcoin prices will not be as expensive as this and this is very reasonable if bitcoin is made to facilitate us in transacting and investing

[krishnapramod]

It is difficult to ponder why 21 million was chosen. Like mentioned above it might involve variables and elliptic curve arithmetic or a much simpler mathemathical explanation (not exactly accurate) like this one:

Calculate the number of blocks per 4 year cycle:

6 blocks per hour
* 24 hours per day
* 365 days per year
* 4 years per cycle
= 210,240
~= 210,000
Sum all the block reward sizes:

50 + 25 + 12.5 + 6.25 + 3.125 + ... = 100
Multiply the two:

210,000 * 100 = 21 million.

Or as mentioned in one of the mails (not sure if they are legit) between Mike Hearn and Satoshi Nakamoto, it was just an educated guess, picking something that was neither too small nor too large, in the middle.

My choice for the number of coins and distribution schedule was an educated guess. It was a difficult choice, because once the network is going it's locked in and we're stuck with it. I wanted to pick something that would make prices similar to existing currencies, but without knowing the future, that's very hard. I ended up picking something in the middle. If Bitcoin remains a small niche, it'll be worth less per unit than existing currencies. If you imagine it being used for some fraction of world commerce, then there's only going to be 21 million coins for the whole world, so it would be worth much more per unit.  Values are 64-bit integers with 8 decimal places, so 1 coin is represented internally as 100000000. There's plenty of granularity if typical prices become small.

https://bitcoin.stackexchange.com/questions/8439/why-was-21-million-picked-as-the-number-of-bitcoins-to-be-created

https://pastebin.com/Na5FwkQ4

https://bitcointalk.org/index.php?topic=2080206.0

[trimulia]

i don't know what about supply,tomorrow i will ask satoshi for this one then inform you

[Willeampere]

Limiting Bitcoin to 21,000,000 is an effort to prevent inflation. Bitcoin value was tried to be kept high on this count. Everyone is wondering what the Bitcoin price will be when this limit is completed.