Take the 2-minute tour ×
English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. It's 100% free, no registration required.

After starting to use the siunitx package for typesetting units (and the numerals before the units) in LaTeX, I noticed that it typesets a single space between a numeral and a unit (a space that is not as wide as a normal space). I have tried unsuccessfully to find a proper reference that calls for this. Wikipedia mentions it on Space (punctuation), but the external reference given on the Wikipedia page, which is in this online .pdf brochure, does not say anything about thin spaces. It only mentions that there should be a space between numerals and units, but says nothing about the size of that space (in which case I think it is reasonable to assume that a normal space is referred to). I have added a question about this in the talk section for the Space article.

What is the proper size of spaces between numerals and units? It would be interesting to know the source for the usage of thin spaces in siunitx, and if that is the way it "really should be".

share|improve this question
I'm going to say this question really is nothing to do with the English language. It's a book design question. Try Graphic Design. Thanks. –  MετάEd Feb 28 '13 at 6:24
@MετάEd But we get questions of whether to use French spacing in English, and take them. –  tchrist Feb 28 '13 at 12:53
I can't say every spacing question is off topic: surely some spacing issues are syntactic and on topic. But this question is nothing to do with syntax and everything to do with graphic design. –  MετάEd Feb 28 '13 at 13:12
@MετάEd We seem to take question abouts whether em dashes should be unspaced, spaced, or thin-spaced. –  tchrist Mar 1 '13 at 0:35
I was unsure of which one to choose, having this one, Graphic Design and Tex - LaTeX as possibilities. The question is not about making it look nice, but rather about what is considered correct use of different space lengths for written English language according to standardizing bodies (like BIPM). If those of you who know these fora better than I do think that it should be moved, that is fine by me. Otherwise (or if it is not possible to move questions) I will just wait a bit to see if I get an answer here, and if not I will just re-post the question elsewhere. –  hjb981 Mar 1 '13 at 1:41

1 Answer 1

You can use either of U+202F NARROW NO-BREAK SPACE or just plain U+00A0 NO-BREAK SPACE, but you certainly should not let it risk being line-broken. I’m not so sure that the thinness matters half so much as the no-break property. You do not want to let the figures get orphaned without their units.

share|improve this answer
The narrow space introduced by siunitx (can also be used anywhere in LaTeX with the command \,) is non-breaking. Before using siunitx, I used the regular non-breaking space (\~). –  hjb981 Feb 27 '13 at 23:41

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.