Spacing between numerals and units of measure

Last Updated : Jul 17, 2012 |

Always include a space between a numeral and the unit of measure.

Example

Verify that the power supply is at 220 VAC.

Exception for compound modifiers

If the numeral and the abbreviated unit form a compound modifier, use a hyphen instead of a space, as the following examples show:

  • A 1.44-MB disk drive

  • A 20-GB cartridge tape drive