Units of measure terms

This section covers usage and abbreviations for a variety of terms related to measurement. For other units of measure not covered here, see The Chicago Manual of Style.

• Use numerals for measurements of distance, temperature, volume, size, weight, pixels, points, and so on—even if the number is less than 10. Add a zero before the decimal point for decimal fractions less than one, unless the customer is asked to enter the value.
  Examples
  3 ft, 5 in.
  1.76 lb
  80 × 80 pixels
  0.75 grams
  enter .75"
  3 centimeters
  3 cm
• Insert a space between the unit of measure and the numeral, or hyphenate if the measurement modifies a noun. Examples
  13.5 inches
  13.5-inch display
  8.0 MP
  8.0-MP camera
• Use abbreviations only with numbers in specific measurements, such as 20 MP, and don't follow the abbreviation with a period.
  Exception Follow in with a period when used as an abbreviation for inch.
• Use commas in numbers that have four or more digits, regardless of how the numbers appear in the UI: 1,093 MB.
  Exceptions
  For years, pixels, and baud use commas only when the number has five or more digits: 1920 × 1080 pixels, 10,240 × 4320 pixels, 9600 baud, 14,400 baud.
  Don’t use commas after the decimal point in decimal fractions.
• When the unit of measure is spelled out, use the singular form when the number is 1. Use the plural form for all other measurements.
  Examples
  0 points
  0.5 points
  1 point
  12 points
• Spell out by in dimensions, except for tile sizes, screen resolutions, and paper sizes. For those, use the multiplication sign (×). Use a space before and after the multiplication sign.
  Examples
  10 by 12 ft room
  3" by 5" image
  4 × 4 tile
  8.5" × 11" paper
  1280 × 1024

Hyphenate half-inch as an adjective. Use instead of half an inch or one-half inch.

When space is limited or the measurement needs to be specific, use 0.5 in.

It’s OK to abbreviate as px in content about online design when space is limited.