Measurements
In text, use measurement abbreviations only when quantities are explicit. In figures and tables, however, always use measurement abbreviations. The treatment of numbers with measurements is described in Numbers.
300 mm
measured in millimeters
Insert a space between the number and most symbols. Do not insert a space before the %, sigma, or s symbol or after the $ or # sign.
0.35 mm
20%
305oC
3s
$100 M
Use a zero before the decimal point of numbers less than one.
0.35