*Billion and
beyond*

There has always
been confusion between what the British and the Americans call a *billion*.
Historically, in the UK, a *billion* is 1,000,000,000,000 (10^12) but in the
US it is only 1,000,000,000 (10^9).

The table below
shows the differences between the two sets of numbers; the only one
which is common to both systems is the *million*.

However, because
of the confusion, the international scientific community started to adopt the US "short scale" version in the 1950s, and UK general usage followed suit (even though
British colloquial use still occasionally reverts to the "long scale", and in British legal circles the long scale is applied).

The table shows
the pattern of why there is a difference. In the UK system, an *-illion*
is considered to be 1,000,000 so that each time you increase the value
with 6 zeros, you go up the scale. So, a *billion* is really
*two -illions*, or with 2*6 zeros, a *trillion* is with
3*6 zeros, a *decillion* is 10*6 zeros and so on, up to a *centillion*,
which is *100-illions*, or 600 zeros.

In the US, the
name represents the number of groups of three zeros after the initial
1,000 - so that a *billion* is two groups of three after the
1,000, or 1,000,000,000 - a *trillion* is three groups of three,
and a *decillion* is ten groups of three zeros after the 1,000
(a total of 33 zeros). The US *centillion* is therefore 1,000
followed by 300 zeros (or a total of 303).

The US system was
modelled on the old French system, but in the 1940s, the French system
was brought in line with the UK system.

US Name |
Zeros |
UK Name |

million |
6 |
million |

billion |
9 |
- |

trillion |
12 |
billion |

quadrillion |
15 |
- |

quintillion |
18 |
trillion |

sextillion |
21 |
- |

septillion |
24 |
quadrillion |

octillion |
27 |
- |

nonillion |
30 |
quintillion |

decillion |
33 |
- |

undecillion |
36 |
sextillion |

duodecillion |
39 |
- |

tredecillion |
42 |
septillion |

quattuordecillion |
45 |
- |

quindecillion |
48 |
octillion |

sexdecillion |
51 |
- |

septendecillion |
54 |
nonillion |

octodecillion |
57 |
- |

novemdecillion |
60 |
decillion |

vigintillion |
63 |
- |

- |
66 |
undecillion |

- |
72 |
duodecillion |

- |
78 |
tredecillion |

- |
84 |
quattuordecillion |

- |
90 |
quindecillion |

- |
96 |
sexdecillion |

- |
102 |
septendecillion |

- |
108 |
octodecillion |

- |
114 |
novemdecillion |

- |
120 |
vigintillion |

centillion |
303 |
- |

- |
600 |
centillion |