Office of Strategic Communications

Style Rules for Numbers


General

1.  Spell out numbers lower than 10 in non-scientific text.

2.  Treat numbers in the same sentence alike: if there's a two-figure number in the sentence, make all the numbers figures, as long as the figures all relate to the same items.

Example:

  • The students collected 14 books for the sale, 3 of which were first editions.
  • Having four meetings made it possible for the 15 committee members to collect 160 used books.

3.  Use either a figure or a word, not both. Five rooms, not five (5) rooms. Delete the parentheses and the 5.

4.  Use the up-to-10-spelled-out/higher-than-10-numeral rule for ordinal numbers (first, second, 12th, 23rd, etc.). This applies to numbered street names as well: Fifth Avenue, 23rd Street.

Addresses

  • In street addresses, building numbers are usually written in arabic numerals: 5801 Ellis Avenue.
  • When a building's name is also its address, the number is spelled out: One Park Place.


Credits, Units

  • Always use numerals: 3 credits; 18 credits in history; a 3-credit course; 4 units of English; 1 unit of geometry; 2 units of a foreign language. Also, use numerals when referring to credit hours. (Note use of "in" with credits and "of" with units.)


Decades

  • No apostrophe: 1920s; 1980s; mid-1970s.
  • Spell out thirties; forties; fifties; sixties; etc.


Fractions

  • Fractions generally are too cumbersome to spell out and should be expressed in numerals, but judge each case on its own.

Examples:

The obstacle was a 3 1/2-foot fence.

They had finished about one-third of the course.


Graduation Years

  • Use an apostrophe (or right-side single quote) preceding the two-digit class year; no comma after the name; no comma before degree designation.

Examples:

Attending the Homecoming reunion were Elise Adams '64 and John Andrews ' 88, '90.

Harold Jones '74 BSEE was the first NCE graduate to win the award.


More Than/Over

  • When referring to something that can be counted, use more than rather than over.

Examples:

More than fifty people attended (not Over fifty people attended).

But: Jason is over six feet tall.


Multiple-Digit Numbers

  • Use a comma for four-digit and larger numbers (except dates): 3,500; 60,000.
  • For very large numbers, use figure and word: 1.2 million, $90 million.


Numbers at the Beginning of a Sentence

  • Always spell out numbers at the beginning of a sentence.
  • Rearrange the sentence if spelling out the number makes it cumbersome.
  • Avoid putting numbers next to numbers -- separate the numbers with words if possible.


Parts of Books

  • Use numerals when you are referring to parts of a book.

Example:

Chapter 4; Table 2.5; page 4


Percent

  • Always use numerals.
  • Spell out percent in text: 5 percent; 9.2 percent.
  • Use the % symbol in charts, graphs, and scientific and mathematical material.


Quantities as Numerals with Abbreviations

  • If a quantity is used with an abbreviation, the quantity always should be expressed in numerals.
  • If a symbol is used with the quantity, use a numeral.
  • For two or more in quantity, the symbol should be repeated.

Example:

3" x 5"; 30' x 50'; 80 km; 2 tsp.


Round Numbers

  • Approximate figures in hundreds, thousands, or millions should be spelled out.
  • Very large figures should be written as numerals, whether they are approximated or not.

Examples:

The company distributed more than one million books.

The nation's population neared 2.3 billion.


Times of Day

  • Use the figure and a.m. or p.m. in both text and schedule listings.
  • Because time designations are not always on the hour, for consistency, use :00 with times that are on the hour.
  • Note that a.m. and p.m. are not capitalized.
  • When possible, drop p.m. or a.m. rather than repeat it.
  • To avoid confusion, use noon and midnight rather than 12:00 p.m. (noon) and 12:00 a.m. (midnight).

Examples:

Classes scheduled for 5:00 p.m. and later have been canceled for today.

The meeting will be held from 4:30 to 6:00 p.m.

I thought he said to meet him at midnight, but he meant that I should meet him at noon.