Why are the UK and American billions different?

What's the difference between a US and a UK billion?
07 February 2017



Tray - why are the English and American billions different to each other and how do they differ?


Chris Smith put this question to maths-man Tim Revell...

Tim - This is one of those issues that is surprisingly contentious considering how dull it really is. To talk you through what are the differences between the Americal billion and the good old fashioned British billion is when you think about how numbers go up - ten tens in one hundred, a thousand thousands in one million, and then what happens next is where things diverge.

In old fashioned British counting a million million used to be a billion. But in America this would be a trillion, so it’s actually a thousand million is a billion. So it’s true there’s no real logic in the American system but there’s also no real logic in the British one either. Because when you get to what is a British trillion, well it’s not a billion billion, it’s a million billion. So it breaks down in both cases.

But actually, now these two things are the same. In the 70s we decided that we’re going to have the same as the American billion and so, overnight, we had huge inflation and what used to be known as a billion became a trillion.

Richard - I’m totally confused. Is it something of just my age where people over 40 were told that there’s this different system?

Tim - In the UK, these things became standardised in the mid 70s, but the confusion has kept ever since. And I think partly in the UK we don’t really like taking things that are American so people fight against it but yeah, the correct way is a thousand million is a billion and, actually, neither of these things are American or British, we took both of these systems from France.

Chris - So they’ve got two system in operation?

Tim - I think in France they also use the same system that we all use now but they created them both and then, for a while, they used both systems but they distinguished between them by calling them the long scale system and the short scale system.


The numbers in the American system get a new name when you add a new comma. It is much easier that way.

Usually it is either very close or completely subjective. But imagine calling a billion 1 thousand million or 100 billion 1 hundred thousand million. The American version is much simpler in the long run and keeps number names from getting too long.

How they differ is easy to find out. I'm more interested in the original question: why?
The fact that one (the long scale, I presume) was in use in France and then the other later popped up, also in France, indicates there was a reason to do it differently.

As an aside, I'm particularly fond of the Japanese language referring to 10^64 as fukashigi, or "unimaginable." One can speak of, for example, 6.4 unimaginables. This is followed by their largest named number, muryōtaisū (10^68), meaning "immeasurable large." Another interesting one is the Indian system which calls 10^67 a gautama. Whether or not this is a reference to the name Gautama, I'm not sure.

Also of interest is the fact that though we more often use myriad to mean "indefinitely large" it more precisely means 10,000. Historically myriad was the largest grouping used before repeating words in Ancient Greece, Rome, and the far East where it continues to be how numbers are grouped (I.e., one, ten, hundred, thousand, myriad, ten myriad, hundred myriad, thousand myriad, myriad myriad). This is reminiscent of other words which have both precise and imprecise usage, such as moment (1/40 of an hour, i.e., 1.5 minutes).

I worry governments attempt to mislead the public and interchange the long and short definition. Is this possible?

a billion is a million of a million like this

But as governments whant to keep ignorant the people they accept the thousand or a million as a billion but the difference is huge like this. a billion and a thousand of a million.
there is a gigantic difference.
A trillion is
every million of a million level adds 6 ceros. Don't get confused.

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