The BTC amount limit...

[MatrixStorm]

I think it is good that there's a limit to the amount of BTC generated over time.
But...why 21 million coins?
Why not like 15 million or 50 million?
I study science, not economy, so can someone please explain this to me?  

P.S.: I already checked out the wiki article about this, so don't redirect me to there please.

[Theo]

I think it went like this: we need some BTC amount to be generated with one block. Let's take 50. Some built-in deflation would be good, so let's half the amount in some intervals. We need to define a minimum and 10^-8 seems reasonable. Put everything in a jar, stir well and you got 21 million max.

[Alex Beckenham]

why 21 million coins?
Why not like 15 million or 50 million?

Why not 140? Or 289,492,592,183,222?

It's just a number.

[Ruudsy]

for real its just a number, but although you can divide one coin into 10^8 units the number of coins should be rather high for economic reasons.
imagine there are only 140 coins, the amount of the smallest units is 140*10^8. in order to set up an international eCurrency this amount should have the ability to represent nearly all goods which are ther to be sold on an international market.

[Alex Beckenham]

for real its just a number, but although you can divide one coin into 10^8 units the number of coins should be rather high for economic reasons.
imagine there are only 140 coins, the amount of the smallest units is 140*10^8. in order to set up an international eCurrency this amount should have the ability to represent nearly all goods which are ther to be sold on an international market.

Your '8' in that equation is also 'just a number'. If there were 140 coins, there might be 140*10^32 units, with the smallest unit being 0.0000000000000000000000000000001 btc.

[Ruudsy]

if we imagine almost small things will be paid with btc then numbers of the form 10^32 will be very unhandy, dont you think?
so 21millions

in near future, when the value of btcs will increase there will be trades for 0.0003btc, that sucks! imagine trades for 0.0000000000075 btc??? i wouldnt like that neither!

by the way in this discussion there will alwasy be an initial nummber, an that will be by definition (just) real ;-) hopefully, so we dont have to pay with imagniary money  think of 5,75i BTC, that woukd e nice ;-)

[willphase]

21million comes from the series:

6 blocks per hour
each block initially contains 50 btc
so that's 7200 btc a day
so 2628000 btc a year
Satoshi Nakamoto wanted the number of btc being issued to half every 4 years
so every 4 years there are 10512000

this halves every 4 years (the bounty drops from 50, to 25, then 12.5 and so on) so in the next 4 years there will be 5256000 generated, then 2628000 then 1314000... it's a series that tends to 10512000 * 2 = 21024000

so the origin of the 21million is 6*50*24*365*4*2 = 21024000

Will

[NothinG]

One exception is the "satoshi" which is smallest denomination currently possible
0.000 000 01 BTC = 1 Satoshi (pronounced sa-toh-shee)

So, shouldn't 1 BTC be able to be split over 10,000,000 people?

[Edit]: Even I've thought about 21mil being a low number...but seeing how far 1 BTC can go; makes you wonder.

[willphase]

yes the smallest bitcoin is to the 8th decimal point, so while there are 21Million BTC in circulation (at end state) there will be 21*1000*1000*1000*1000*10 smallest units.

It's like saying there are only N number of 100dollar bills so how will there ever be enough for everyone - well, there's the penny

Will

[remssik]

The largest problem I can see in the future here is the fact that .00000000075 and .0000000075 look rather similar. This could lead to an immense amount of confusion and scamming, if not dealt with.

The advantages of other currencies without a limit (and with inflation) are:
A) Most deal in whole numbers, which have commas to help combat scamming (e.g., 10,000,000 and 100,000,000 are easily seen as different due to commas).
B) Most have smaller denominations with names (e.g., cents of the USD).
C) Incredibly small denominations are rare (due to inflation).

I am by no means advocating other currencies (go Bitcoins!), but something may need to be done at some point. Two potential options:
A) Introduce smaller units (like cents, Bitcents!).
B) Universally announce that .0001 old Bitcoins = 1 new Bitcoin periodically (like they did in Zimbabwe (on second thought, probably not a good idea here)).

Comments?

-Rem

[willphase]

yes there is a potential nomenclature issue - it's been discussed at length in the bitcoin forums.  There isn't really a consensus on what to call the smaller items, and whether it's worth starting to use the term BTC for e.g. 1000BTC...  a bit like calories

The gram calorie, however, is a very small unit for use in nutritional contexts. Larger units are therefore used. The kilocalorie (symbol: kcal), being 1000 small calories, is one such unit. The large calorie, usually referred to simply as calorie, is also used. These are equivalent (1 kcal = 1 Cal).[2] Therefore, in nutritional contexts the calorie and kilocalorie are the same size.

Are you confused yet?

Will

[remssik]

Haha, I'm familiar with the whole Calorie thing  , though it's messed me up on occasion before  . We could use the standard for it http://www.knowledgedoor.com/2/units_and_constants_handbook/power_prefixes.html . That's probably the most well known option.

[NothinG]

How about using commas backwards?

0.000,000,01 BTC

[shiprat]

21M Is a pretty number?

[remssik]

NothinG you read my mind, or perhaps I read your...  

[NothinG]

NothinG you read my mind, or perhaps I read your...  

My dot's are protected o.D

[Bert]

Sound pressure level is measured in decibel (dB). A decibel is one tenth of a bel, a seldom-used unit. Over time with only 21 million bitcoins, BTC will become less used and smaller unit such as mBTC/uBTC/mmBTC will become the norm.

[Ruudsy]

21million comes from the series:

6 blocks per hour
each block initially contains 50 btc
so that's 7200 btc a day
so 2628000 btc a year
Satoshi Nakamoto wanted the number of btc being issued to half every 4 years
so every 4 years there are 10512000

this halves every 4 years (the bounty drops from 50, to 25, then 12.5 and so on) so in the next 4 years there will be 5256000 generated, then 2628000 then 1314000... it's a series that tends to 10512000 * 2 = 21024000

so the origin of the 21million is 6*50*24*365*4*2 = 21024000

Will

a converging series is a nice explanation for the 21mil, but who said we need 6 blocks per hour? just another real number ... and who stated that in the beginning there were 50btc per block? just another real number ...

so the problem is reduced to its root, i might say ;-)

[BlackHatCoiner]

I would like to dig up this thread.

So, to sum up, if we take this formula:

50÷1, after 4 years 50÷2, after 4 years 50÷4 and so on we will end up someday. The numbers of course will never reach zero but since nakamoto decided that the smallest bitcoin unit is 0.00000001BTC then when it will reach 0.000000005BTC , it won't count. So it will be considered as zero to us.

The thing I don't get is why each 210240 blocks, rewards must get halved. And also, why 6 blocks are getting mined every 1 minute?

Thanks to anyone that will help me solve my question.