Writing style: no space between numbers and units (except when non-abbreviated)

I had a bit of a scare the other day: an agency I do a lot of work for sent an important brochure to a proofreader after I’d written all the text for it, and it came back with a few comments. A few things were a matter of style, and then there was one “correction” that caught me off guard.

According to the anonymous guru of grammar, I should have omitted the spaces between numbers and units – so instead of “60cm” it should be “60 cm”. What?

The Guardian style guide

I thought that looked a bit odd, so I turned to the trusty Guardian Style Guide for help. I couldn’t find anything in there, so I thought I’d try asking them on Twitter.

I live to write another day

Their curt but relieving reply was:

So it turned out I was right, or at least according to the Guardian. And that’s enough for me.

The International System of Units

Fair play to the proofreader, the International System of Units (SI) – so international that its acronym is French – stipulates that there is a space before an abbreviated unit. However, I wasn’t writing a scientific paper, so just as I ignore the SI when separating thousands with commas, I will ignore it in this case too.

The Telegraph style guide

The Telegraph has a style guide too, and despite being on the other end of the political spectrum from the Guardian, in this they are in agreement: although their style guide doesn’t directly mention it, in the section entitled “Numbers, measures and money”, it clearly departs from the SI and stands shoulder to shoulder with the Guardian: thousands are cleft by commas, and quantities joined to their units.

Conclusion

So there we have it. For non-scientific writing, there’s no space between the number and the unit if it’s abbreviated. If the unit isn’t abbreviated, then – fairly obviously – there is a space. So 60cm or 60 centimetres.