Units of measure

In general, numerals work well for expressing computer-related measurements and other units of measure on the Web—numerals save space, and they tend to catch the eye of a scanning reader. But beyond this general guideline, you have a number of choices to make. For instance, you could express the dimensions of a painting as 11 by 14 inches, 11 by 14 in., or 11" x 14". In part, your choices will be based on the kind of website you have and its features and needs.

Some best practices to govern your decisions:

• Use numerals when referring to physical dimensions: height, width, length, depth, weight, mass, volume, distance, type size, and so on.

Examples
He ducked to go under the 7-foot doorframe.
The fish weighed 8 pounds and was nearly 2 feet long.
We had already walked 5 miles when she noticed it was missing.
An 8-point font is hard to read.

• With units of time (minutes, hours, days, weeks, months, and so on), follow the regular number rule: Spell out one through nine, use numerals for 10 and above.
• Two exceptions:
  • If your content is scientific, statistical, or technical, use numerals with units of time.
  • Use numerals in tables or graphs and other areas with space constraints.

Examples
Do you have five minutes?
We missed the first 20 minutes.
In our control group, Mouse C1 completed the maze in 9 seconds; Mouse C2, in 7.5 seconds. (Exception for scientific material)

• Use a hyphen for adjectives: a 9-foot crocodile. But don’t use a hyphen if you abbreviate the unit of measure: a 9 ft. crocodile.
• For English units of measurement (inches, feet, yards, and so forth), use either the symbol, if one exists (for example, a double straight quote for inches, a single straight quote for feet), the full word, or the abbreviation with a period (for instance, in., ft., yd.). Use your choice consistently throughout your site or product. For instance, you might decide to always spell out the unit in your text but to use either abbreviations or symbols in tables and other tight spaces.
• The plural and singular forms of abbreviations are the same—don’t add an s to the end. For example, in. is the abbreviation for both inch and inches.

• For metric units of measurement, use either full words (centimeters, meters, kilometers, and so on) or abbreviations (cm, m, km) consistently. Don’t use periods with metric abbreviations, and don’t add an s to form plurals: 1 mm, 35 mm.

• If you’re using a symbol to express a unit of measure, don’t put a space between the numeral and the symbol: a 9' crocodile. Similarly, don’t put a space between numerals with different units of measure: a 9'6" crocodile.

Examples
Sam Long, the 7-foot-3-inch center, carried the flag for the Smithtown team.
Sam Long, the 7 ft. 3 in. center, carried the flag for the Smithtown team.
Sam Long, the 7'3" center, carried the flag for the Smithtown team.

• When describing two or more dimensions of an object such as a photograph or a poster, follow these guidelines:
  • If using symbols: Repeat the symbol for each figure. Separate the dimensions with an x. A space before and after the x is optional—as long as you’re consistent.

Example

Order 4" x 6" or 8" x 10" prints.
Order 4"x6" or 8"x10" prints.

• If using full words or abbreviations: Do not repeat the word or abbreviation for each figure unless different units appear. Separate the dimensions with an x or the word by.

Examples
She rented a 10 x 12 ft. room.
She rented a 10 ft. 6 in. x 12 ft. 10 in. room.

• Don’t use a hyphen with abbreviated units even if you are listing two dimensions. Do use a hyphen when you are spelling out the units.

Examples
The room had a 1.5 by 2 ft. window.
The room had a 1.5-by-2-foot window.

• Use numerals with these other units not commonly considered units of measure:
  • Digits or characters making up a code, password, or other string of characters in a technical context
  • Units related to sports scores

Examples
Please enter a 5-digit ZIP code.
Enter an 8-character password.
The Australian team is ahead by 2.

For unit abbreviations you don’t find listed here, see the Yahoo! word list.

Technical requirements for products or features often include computer- and software-related numbers that need special treatment.

Storage, memory, and processor speeds

Use the following abbreviations to describe storage and memory sizes or processor speeds.

When describing storage or memory requirements:

• Don’t put a space between the number and the abbreviation for the unit.

Examples
Increase your memory from 2GB to 4GB.
System requirements include a 1.3GHz Pentium 4 processor, 512MB of memory, and 1GB of disk storage.

• Don’t add an s after the abbreviation to form a plural.

Example
Before
You can purchase an additional 2GBs of storage.
After
You can purchase an additional 2GB of storage.

• Repeat the abbreviation in a series.

Example
Get a 2GB, 3GB, or 4GB external hard drive for extra storage.

Other technical numbers and abbreviations

Examples
Download files at speeds starting at 600 kilobits per second (Kbps). Upload files at speeds starting at 500Kbps.
Experience a 600Kbps connection.
Watch the slideshow on a monitor set at 1,024 x 768 pixels.
Photos submitted for the contest must be at least 300 dpi.
The DVD-RW drive boasts write, rewrite, and read speeds of 16x, 8x, and 16x, respectively.