What is the right preposition in

The human's weight is (of/in) the order of 10^2 kg.

Are both correct, or do they have different meanings? I found both in the internet and I found many discussions on this question without a solution. I guess SX is ideal to find a short solution.

  • 3
    I would say it is on the order of ...
    – Robusto
    Dec 15, 2012 at 14:55
  • 3
    The idiom is on the order. Occasionally one sees of the order in discussions of magnitude, but that's a very specialized usage. Dec 15, 2012 at 17:42

3 Answers 3


In the UK, the idiom is of the order of (at least, in the example quoted, "of the order of 100kg").

In [the] order of specifies a sequence; and on the order of specifies who made an edict.

ODO entry:

of the order of: approximately; having the order of magnitude specified by...

  • 1
    And, writing 10^2 kg or 10² kg is unusual to point of being highly irregular.
    – Andrew Leach
    Dec 15, 2012 at 18:06

The vast majority of these citations from Google Books will probably all match OP's context...

...distance is of the order of... 6670 results

...distance is in the order of... 1050 results

...distance is on the order of... 907 results

Whilst I don't see clear-cut reasons for saying any particular preposition is either "right" or "wrong", I personally prefer in. The repetition of of slightly turns me off the first alternative, and I simply don't come across on very often, so it seems a little "strange" to my ear.

I would also just say the ratios implied by figures are only an approximate guide to actual usage. The corresponding figures for "weight" are of:2680, in:1150 on:396. But the basic message is they're all used reasonably often, but of is the most common form.

  • 'Of the order' likely gets a big boost in google books via the use of 'order' in taxonomy: en.wikipedia.org/wiki/Order_(biology) Dec 15, 2012 at 22:44
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    @Wayfaring Stranger: That would seem vanishingly unlikely, bearing in mind that I specifically preceded the expressions by distance and weight in my searches. I suppose somebody could have written something like "The monarch butterfly, which migrates an incredible distance, is in the order of Lepidoptera". But that ain't gonna skew the usage figures significantly. Dec 15, 2012 at 22:59

The Google Ngram Viewer, as a tool aiming at quantitative results, is more suitable than Google Books. It shows the usage versus time. The result is much more pronounced in favour of "of", especially before 1950 (before US contribution to technical literature became dominant), and places "on" ahead of "in" (compare comments to the question).

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