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Large numbers are numbers above one million that are usually represented either with the use of an exponent such as 109 or by terms such as billion or thousand millions that frequently differ from system to system. The American system of numeration for denominations above one million was modeled on a French system, but in 1948 the French system was changed to correspond to the German and British systems. In the American system each of the denominations above 1,000 millions (the American billion) is 1,000 times the preceding one (one trillion = 1,000 billions; one quadrillion = 1,000 trillions). In the British system each of the denominations is 1,000,000 times the preceding one (one trillion = 1,000,000 billions) with the sole exception of milliard, which is sometimes used for 1,000 millions. In recent years British usage has reflected widespread and increasing use of the American system.
The table provides American and British names for various large numbers.
| value in powers of ten | number of zeros | American name | British name |
|---|---|---|---|
| 109 | 9 | billion | thousand million or milliard |
| 1012 | 12 | trillion | billion |
| 1015 | 15 | quadrillion | thousand billion |
| 1018 | 18 | quintillion | trillion |
| 1021 | 21 | sextillion | thousand trillion |
| 1024 | 24 | septillion | quadrillion |
| 1027 | 27 | octillion | thousand quadrillion |
| 1030 | 30 | nonillion | quintillion |
| 1033 | 33 | decillion | thousand quintillion |
| 1036 | 36 | undecillion | sextillion |
| 1039 | 39 | duodecillion | thousand sextillion |
| 1042 | 42 | tredecillion | septillion |
| 1045 | 45 | quattuordecillion | thousand septillion |
| 1084 | 84 | quattuordecillion | |
| 10100 | 100 | googol | googol |
| 10303 | 303 | centillion | |
| 10600 | 600 | centillion | |
| 10googol | googol | googolplex | googolplex |
This article was most recently revised and updated by Erik Gregersen.
