When to "move the decimal points" ?

[Gavin Andresen]

Bitcoins are 50 times more valuable today than when I first heard about them six months ago.  If they just double in the next six months, they'll have risen 100-fold in a year.

It seems like a good idea to me to come to a consensus now about when to "move the decimal points" -- when should the Bitcoin program allow you to specify payments with more than two decimal places (e.g. "pay Gavin 0.001 BTC for his thoughts") ?

When should the Bitcoin program assume you're entering payments in 'millicoins' or 'microcoins' ?

And when should all of the internal minimums (e.g. smallest transaction fee or the trigger for the 'micro-transaction spam prevention') be lowered?


Here's a straw-man off the top of my head:

When Bitcoins are worth more than about ten dollars (or euros) each, I think it'll be time to allow sub-bit-penny payments.  And I think the "smallest free transaction" limit (and other internal minimums) should move in lock-step with that change.

When 1 Bitcoin is worth somewhere around $100 (in 2010 dollars), I think it'll be time for the client to switch to millicoins (e.g. .001 BTC), so if I'm buying a paperback book it costs 50 milliBTC  instead of  .05 BTC.

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[MoonShadow]

I think that it's already past time to set a block number for the decimal point shift.  At the rate the value is rising, if we set the block number in a predictable future and then start releasing clients that are aware of it, perhaps the change will be without confusion.  If not, then there will be clients out in the wild that don't represent the value in the same way, and confusion in a transaction with newbies who don't understand that a change in ongoing could be a very bad mark on Bitcoin's rep.

[theymos]

I think Pecunix allows you to transfer 0.0001 GAU, so I would add another decimal of allowed precision when 0.01 BTC is worth more than 0.0001 GAU (pretty soon, if prices keep rising).

The decimal should be moved when transfers over 1 BTC are less than 1% of all real transactions. So probably not for a long time.

[FreeMoney]

5 cents seems like a reasonable amount to ensure can be sent on the network. A cheap piece of candy is a reasonable minimum tip for an article/video. Once you can't send a nickel I think that's where a loss of utility starts.

Eventually generators will set their own fees, but as long as most people are using Satoshi's software's suggestions (wow, say that 5 times fast), I think this would be a reasonable goal.

[ribuck]

People have a certain familiarity with two decimal places (by analogy with many fiat currencies) so I don't think the change should be made any earlier than necessary.

More decimal places will cause a certain amount of confusion, and will need to be handled carefully in the user interface.

[FreeMoney]

People have a certain familiarity with two decimal places (by analogy with many fiat currencies) so I don't think the change should be made any earlier than necessary.

More decimal places will cause a certain amount of confusion, and will need to be handled carefully in the user interface.

Yes, would switching to 'BitMils' be clear enough? So .01BTC now would appear as 10BTM and then decimal places could be added from there as it became reasonable? I think this system can get us down 1000x from where we are now without any confusion.

In the transition there can be a very clear toggle button in the software so that people have to switch it manually the first time and are therefore completely aware, the toggle switch would also change how the balance would be displayed.

[da2ce7]

I think that we should put the 3rd decimal place in immediately, however pop up a warning if the transaction is less than the transaction fee(leave the transaction fee as it is).  I think that will be a useful tool to educate people about transaction fees.

Much later on (aka a year), we should change the units from BTC to BTCe-3. (and the associated extra 3 decimal places of precision).  The client should then have options to have BTC, BTCe-3, or BTCe-6 as it units. (each with 3 decimal places of precision... in th GUI)

At that point, allow people to choose a transaction fee of their choice.  The client software should also provide some statistics on how long it takes for a transaction of any given fee to be included in the block chain (based upon the block history), and a warning if the fee is likely to be wasteful.

I think the current system where the transaction fees are invisible gives a false impression on how the network works.

[MoonShadow]

I think the current system where the transaction fees are invisible gives a false impression on how the network works.

The system is difficult to wrap one's head around anyway, but I think that you are right about the hidden nature of transaction fees.

[caveden]

I think it's too early yet. 0,01BTC is still quite an insignificant amount.
And there is no need to try to predict the future by setting this change to happen automatically at block X. We can wait for the value to raise before performing such change. It's not like 1BTC will suddenly reach U$10,00 value.

By the way, I also think it's better to display with 1mBTC than 0,001BTC.

[ribuck]

Why not keep the behavior for new installs exactly as it is now, to keep it as simple as possible for new users.

But add a user preference for "number of decimal places" so that anyone who wants more decimals can experiment with having more. I don't think there's any reason why every client needs to display the same number of decimal places.

The block chain already contains transactions with more than the two decimal places displayed by the standard client.

[JohnDoe]

I think it would be a good time when 0.01 BTC is worth more than 1 cent.

Much later on (aka a year), we should change the units from BTC to BTCe-3. (and the associated extra 3 decimal places of precision).  The client should then have options to have BTC, BTCe-3, or BTCe-6 as it units. (each with 3 decimal places of precision... in th GUI)

Agreed, but it would be easier to name them mBTC (mili bitcoin), µBTC (micro bitcoin), nBTC (nano bitcoin), etc.

[ribuck]

µBTC (micro bitcoin)

I like this, but it's a real pity that the general public don't widely understand this metric prefix. It can also be typed as "u" instead of "µ" (electrical engineers are quite comfortable abbreviating microFarad as uF).

But many UK newspapers, including the Daily Mail, still refer to a microgram as "mcg" instead of "µg" or "ug". It's rather pathetic.

[bitcoinex]

My experience: I used the yuan in China. They have three units of currency:

1 CNY (yuan)
1/10 CNY = 1 jiǎo (角)
1/100 CNY = 1 fēn (分)

So, it is very inconvenient. Often confused between jiǎo and fēn. Most Europeans are also confused.

Please do not start using a new name, just enable using of 0.001 for BTC.

[ShadowOfHarbringer]

Agreed, but it would be easier to name them mBTC (mili bitcoin), µBTC (micro bitcoin), nBTC (nano bitcoin), etc.

This is theoretically good, however it is not enough. When bitcoin goes into 6th or 8-th decimal place, You will run out of prefixes which can be recognized by more than 1% of general population...

[ShadowOfHarbringer]

My experience: I used the yuan in China. They have three units of currency:

1 CNY (yuan)
1/10 CNY = 1 jiǎo (角)
1/100 CNY = 1 fēn (分)

So, it is very inconvenient. Often confused between jiǎo and fēn. Most Europeans are also confused.

Please do not start using a new name, just enable using of 0.001 for BTC.

I propose a new way to distinguish between bitcoins with different decimal numbers - BTCX.

1 BTCx0 = 1 BTC
1 BTCx1 = 0.1 BTC
1 BTCx2 = 0.01 BTC
1 BTCx3 = 0.001 BTC
1 BTCx4 = 0.0001 BTC

... and so on.

I know that it may look weird, but i think this is the most intuitive way describing different-sized parts of the same currency.
Unless somebody knows a way to further improve this.

EDIT:
Perhaps some other character that looks better can be used instead of "X" - for example:

Code:

1 BTC-0 = 1 BTC
1 BTC-1 = 0.1 BTC
1 BTC-2 = 0.01 BTC
1 BTC-3 = 0.001 BTC
1 BTC-4 = 0.0001 BTC

[JohnDoe]

This is theoretically good, however it is not enough. When bitcoin goes into 6th or 8-th decimal place, You will run out of prefixes which can be recognized by more than 1% of general population...

Actually the 8th decimal would use the micro prefix as micro stands for 10^-6, so the lowest possible unit would be 0.01 µBTC.

[MoonShadow]

5 cents seems like a reasonable amount to ensure can be sent on the network. A cheap piece of candy is a reasonable minimum tip for an article/video. Once you can't send a nickel I think that's where a loss of utility starts.

Eventually generators will set their own fees, but as long as most people are using Satoshi's software's suggestions (wow, say that 5 times fast), I think this would be a reasonable goal.

I disagree, there are many things that a payment of less than a nickel should be possible, such as per-email or per SMS usage of bandwidth.  I don't know that we would ever have a per-email charge system anywhere, but the main reason that we never have had such a thing is that the economies of scale combined with the inefficencies of fiat-credit exchanges make usage tolls on bandwidth prohibitively expensive.  Just think about the differences between the all-data cell packages and the per SMS or per-KB cell packages of today and yesteryear.  One doesn't have to be a particularly heavy messaging user to quickly justify the fixed monthly cost of unlimited data & texting.

[nanotube]

I suggest to remove all mandatory rounding. If i want to send 1.02345 btc, I should damn well be able to. (Well, I still can, with a modified client... but I shouldn't need to modify the client.)

The 'max 8 decimal places' can stay for a while... but the forced rounding should go. Now, the client may still trim trailing zeros to neaten display, that would be fine, but forced rounding has got to go.

As far as "moving decimal point"... I think maybe instead the client should just acquire a dropdown box next to the balance display and other amount displays, where you get to choose the units (bitcoins, bitcents, microcoins, etc). As bitcoin value goes up, the "default" unit may change, but full-coin-unit display should always be possible.

Just my 0.0298723 BTC

[MoonShadow]

The 'max 8 decimal places' can stay for a while... Just my 0.0298723 BTC

The 'max 8 decimal places' will have to stay for a long while, since that is a byproduct of how the bitcoin value is stored.  It's a very long (binary?) integer (64 bit, I think) and has no decimal point.  The clients simply display the values with a decimal point in the middle of the base 10 translation of the  integer, as there are 8 decimal places to each side of the display.  Changing that might prove to be a breaking change, and may not be an easy one.  I don't know how difficult it would be to switch to an 128 bit integer, but since I don't think that there is any OS that yet process 128 bit natively I imagine that might have to come first.

[jimbobway]

Using bitcoind server it's possible to send decimals under .01 right?  I think the default bitcoin client should by default show .01 but it should be adjustable in the menu.