Reminder. Insert a nonbreaking space between a number and its unit.
To insert a nonbreaking space:
Use Ctrl+Shift+Space (Windows), or Option+Space (Mac).
A unit symbol has either an alphabetic basis (eg km, kg) or a nonalphabetic basis (eg $, %).
Always use arabic numerals (not words) for numbers used with a symbol:
Do not use a symbol without a number:
Weight was measured in kilograms. not Weight was measured in kg.
Separate an alphabetic symbol from a number with a nonbreaking space. An alphabetic symbol is always singular – do not add an s to the end – and is not followed by a full stop unless it occurs at the end of a sentence:
1 g 18 mm 7 L 2 km 300 m2 pH 7
A nonalphabetic symbol is usually closed up to the number:
$10 20% <20 50× [magnification] 90° angle
except if it is a mathematical operator (in which case a nonbreaking space is used each side of the operator; see Mathematical operators), degree Celsius or the SI unit ohm (in which cases the number and unit are separated by a nonbreaking space):
However, expressions that use < or > and a measurement or number should generally only be used in parentheses or in tables; in running text, replace the symbol with a word:
Overnight temperatures for July were less than 2 °C.
Average night-time temperatures varied (<2 °C in June, >10 °C in January).
Did you know? In Microsoft Word, a nonbreaking space appears in the text like a ‘degree’ symbol: °.