# [texhax] Units in technical writing

Reinhard Kotucha reinhard.kotucha at web.de
Thu Dec 29 03:22:16 CET 2011

On 2011-12-28 at 16:04:28 -0800, Robert Wilson wrote:

> I'd like to ask a related question on what is the appropriate way to
> typeset units. Italic?

No, units are typeset upright always.  Only variables are typeset
italic.  Operators like d (differential) or i, j (complex) or e
(exponential) are typeset upright.  They are not variables.

And text is always upright, even in math formulas:

If you look at the output carefully, you see immediately that the
latter variant must be wrong (no ligaturtes, awful kerning).

> Space between number and unit?

Yes, or maybe better a thin space (\, in LaTeX).

> I've never been able to find an authoritative style guide.

I'm sure there are ISO standards but I fear that you have to pay for a
copy.  You'll probably find them in a library of a university.

Another valuable source is TUGboat, http://tug.org/TUGboat .  There
are often quite interesting articles about math typesetting.

The siunitx (LaTeX) package has all the rules built-in.  It's also
worthwhile to consult its documentation.  The reference section

And even if you don't read anything at all, there is a simple rule:
Everything within a math formula has to be unambiguous.  If variables
are italic, units have to be typeset differently.

Regards,
Reinhard

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