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WSU Editorial Style Guide

Numbers below 10 are spelled out.

  • Exception: Percentages, semester hours, and grade point averages.
    • 10 percent, 3 semester hours, 3.5 grade point average (unless the number begins a sentence).
    • Enrollment increased by 25 percent. Twenty-five percent of the students were over the age of 20.
  • Exception: It is sometimes better to use numerals in ads, posters, and websites for ease of reading.
  • Treat numbers alike in a sentence if they refer to the same thing: “The class of 150 students was separated into smaller groups of 4 students each.”

Use “more than” rather than “over” with numerals.

  • “Enrollment is more than 18,000 students.”

Numbers at beginning of sentences

Always spell out numbers at the beginning of a sentence or reword the sentence to avoid spelling out a large number.

Ordinal numbers

Spell out ordinals in text.

  • first
  • second
  • tenth
  • Not 1st, 2nd, 3rd

When ordinal numbers are needed (as in rankings), do not use superscript letters.

  • “The program is ranked 16th in the nation” (not 16th).

Ordinals are never needed with months and days.

  • “On May 2, the program began” (not “On May 2nd”).

Numbers of four digits or larger

Use a comma for larger numbers.

  • 1,500
  • 35,000

Very large, round numbers should be expressed with a figure and word.

  • 450 million
  • $2 billion

Exceptions: Dates (1892), temperatures (-1200 degrees), and test scores

Decimals and fractions

List decimals and fractions in figures.

  • 1.25
  • 2/3

In some cases, a fraction may be spelled out.

  • “The professor covered about two-thirds of the chapter during the class.”
  • Note that hyphens are used when spelling out fractions.


Figures plus a.m. or p.m. (lowercase with periods) are used to designate time in both text and schedules.

  • “The lecture will begin at 10:00 a.m. with a luncheon to follow at noon.”
  • Meeting: 5 p.m.
  • Note that “noon” is lowercase and is not used with 12:00.

Plurals of numbers

List plurals by adding an “s.”

  • 5s
  • 20s
  • 1980s

Centuries and decades

Spell out centuries and decades where possible.

  • fifteenth century
  • the sixties

If using figures, they should have an “s” at the end.

  • 1960s
  • ’60s

Telephone numbers

Write telephone numbers with a hyphen after the area code.

  • 509-335-3518
  • Do not use a 1 to precede the area code: 800-335-3518

Numbers between -1 and 1

Use plural, not singular, for fractional numbers less than 1.

  • 0.4 miles, not 0.4 mile