Maximum number of bitcoins

[ploum]

We all know here that there's a maximum number of bitcoin which is 21 million.

The answer to "what if we need more" is : we can always divide bitcoin.

Problem: bitcoin cannot be divided infinitely. It means that there's an absolut limit on the possible number of bitcoin. This number might look huge.

But remember: 640k was enough memory for anyone.

So, if it happens that we reach the maximum possible division of bitcoin, what will happen? Economicaly speaking and technically? What will we do?

[davout]

bitcoin cannot be divided infinitely.

Yes it can.

We all know here that there's a maximum number of bitcoin which is 21 million.

The answer to "what if we need more" is : we can always divide bitcoin.

Problem: bitcoin cannot be divided infinitely. It means that there's an absolut limit on the possible number of bitcoin. This number might look huge.

But remember: 640k was enough memory for anyone.

So, if it happens that we reach the maximum possible division of bitcoin, what will happen? Economicaly speaking and technically? What will we do?

Store amounts with more precise representations.

[0x6763]

Problem: bitcoin cannot be divided infinitely.

Economicaly speaking and technically? What will we do?

Who needs an infinite number of bitcoins anyway?  There are a finite number of potential bitcoin users.  An infinite currency is a worthless currency.

Bitcoin can be updated to allow for higher divisibility than it currently supports if deemed necessary (far in the future if ever), and is currently divisible more than anyone currently (or for the foreseeable future) needs in any practical sense.

[FatherMcGruder]

Problem: bitcoin cannot be divided infinitely.

Neither can gold. You can divide it down to the atomic level. To go past that you need fission, but you'll end up with whole isotopes of yttrium and zirconium (or something) instead of half atoms of gold.

Perhaps we'll need a bitcoin fission reactor. Feed it a bitcoin, get at least two betacoins.

[BioMike]

Get a second "branch" (new genesis block) of bitcoins. EUcoins, USAcoins, Chinacoins, etc.

[Luke-Jr]

We all know here that there's a maximum number of bitcoin which is 21 million.

20,999,999.9769 BTC actually.

Who needs an infinite number of bitcoins anyway?  There are a finite number of potential bitcoin users.  An infinite currency is a worthless currency.

There are an infinite number of potential bitcoin users, until the end of the world. Currently, the world population is a mere 6.7 billion, and there is more than enough land in Texas for every last one of us to have our own house. If BitCoin succeeds long-term, we will need much more base units. But that's so far off, it's not worth bothering with now.

[ShadowOfHarbringer]

Get a second "branch" (new genesis block) of bitcoins. EUcoins, USAcoins, Chinacoins, etc.

What for ?

I will stay with the main branch, thank you.

[Gavin Andresen]

2.1 quadrillion basic units should be plenty.  The US M2 money supply is (according to Wikipedia) less than 1 quadrillion pennies.

If bitcoin is ever twice as popular as dollars, that would be a very good problem to have.

[ploum]

If bitcoin is ever twice as popular as dollars, that would be a very good problem to have.

Thanks for confirming my understanding.

Now, I'm playing devil's advocate here: why would I invest in a money that has a physical limit like this? See the year 2000 bug and the IPv4 story: the problem seems far far far away and, one day, we wake up and the problem is there.


Now, one possible solution I foresee would be to run a second bitcoin network. The clients would operate on both networks in a way transparent to the user. If you have 10BTC, you could, in fact, have 8 on the old network and 2 on the new one. The "only" problem would be that BTC addresses would have to differentiate from one network to another. We could imagine adding "@2" at the end of the addresses. An BTC address without "@2" (or with "@1") would be considered as part of the first network, which allows backward compatibility.

[Mike Hearn]

This is like saying the quantity of dollars is limited by the amount of paper in the world. 2.1 quadrillion is a huge number, the planet isn't getting any bigger and the worlds population is projected to peak at 9 billion people. We have bigger problems

[davout]

Now, I'm playing devil's advocate here: why would I invest in a money that has a physical limit like this? See the year 2000 bug and the IPv4 story: the problem seems far far far away and, one day, we wake up and the problem is there.

Haha yea that's right, the year 2000 bug totally destroyed the internet, so will the ip4 shortage.

[Local]

If bitcoin is ever twice as popular as dollars, that would be a very good problem to have.

Thanks for confirming my understanding.

Now, I'm playing devil's advocate here: why would I invest in a money that has a physical limit like this? See the year 2000 bug and the IPv4 story: the problem seems far far far away and, one day, we wake up and the problem is there.


Now, one possible solution I foresee would be to run a second bitcoin network. The clients would operate on both networks in a way transparent to the user. If you have 10BTC, you could, in fact, have 8 on the old network and 2 on the new one. The "only" problem would be that BTC addresses would have to differentiate from one network to another. We could imagine adding "@2" at the end of the addresses. An BTC address without "@2" (or with "@1") would be considered as part of the first network, which allows backward compatibility.

This would be reasonable if the problem was like "It breaks completely and there are no possible solutions at any cost", but it isn't that bad at all. There are many solutions that won't be very hard to implement. And so what if it cost $1B to fix the thing, that's like 1BTC by that point. 

[ShadowOfHarbringer]

Second network... ? Alternative chain...?

The Bitcoin is divisible enough, and protocol supports even more divisibility, so what exactly are we discussing ? I thought this matter is already resolved.

[ploum]

According to my understanding of bitcoin and to gavin, you cannot infinitely divide a bitcoin. Thus, the maximum of possible BTC units is 2.1 quadrillion.

I'm thus trying to think about what we could do if we want more units. (currently, it's a pure intellectual challenge for the sake of it).

[ShadowOfHarbringer]

According to my understanding of bitcoin and to gavin, you cannot infinitely divide a bitcoin. Thus, the maximum of possible BTC units is 2.1 quadrillion.

I'm thus trying to think about what we could do if we want more units. (currently, it's a pure intellectual challenge for the sake of it).

Well, i think i remember Gavin (or maybe it was somebody else ?) saying some time ago, that this is not a hard limit, and the protocol/client can be upgraded in future versions to support even 128 digits of precision.

Isn't this right, Gavin ?

[ribuck]

... this is not a hard limit, and the protocol/client can be upgraded in future versions to support even 128 digits of precision

There are a number of possible solutions, if more precision is ever required. One of them involves using the existing "sign bit" to represent a precision shift of the remaining bits of the 64-bit amount.

But really there's no point planning for this now. The world will have changed in unimaginable ways if ever Bitcoin gets to the point of needing more precision.

[ShadowOfHarbringer]

... this is not a hard limit, and the protocol/client can be upgraded in future versions to support even 128 digits of precision

The world will have changed in unimaginable ways if ever Bitcoin gets to the point of needing more precision.

+ 1

I should print this out and put it on the wall over my desk.

[myrkul]

On Security Now, A listener asked a very intelligent question, which fits into this discussion quite well:

With real (minted) currency, a hole in my pocket results in change dropped onto the ground, lost.

With Bitcoins, a hard-drive crash or un-backed-up wallet, results in bitcoins lost into the ether, gone.

The difference is, with minted currency, someone can come along and pick up that change. If my 50 BTC wallet is gone forever, so too is that 50 BTC. Now, obviously, that reinforces the necessity of backing up your wallet after every transaction (Which I do), but someone, somewhere, isn't going to. This will result in deflation, slowly, over time.

Is there a solution to this?

[mpkomara]

Is there a solution to this?

A solution to what?  Don't lose your bitcoins.

[myrkul]

Is there a solution to this?

A solution to what?  Don't lose your bitcoins.

Problem is, If I lose bitcoins, the market loses bitcoins. The solution I'm looking for is to the inevitable deflation. If Bitcoins are to be a stable currency, it must be, you know... stable.