Using Numbers in Writing

For Modern Language Association (MLA)

If you are writing about literature or another subject that involves infrequent use of numbers, you may spell out numbers written in one or two words and represent other numbers with numerals (MLA Handbook for Writers of Research Papers 81-85).

Examples:

  • Words:

  • thirty-one years

  • eighty-three people

  • Numbers:

    • 275

  • Both:

  • 4.5 million

Numbers:

  • Quantities involving units of measurement:

    • only $31.50

    • 4.78 liters

    • 99.25 percent (in non-scientific contexts)

    • 25% (in scientific contexts)

  • Numbers in dates:

    • December 12, 1965 or 12 December 1965

    • A.D. 1066

    • in 1971-1972

    • the 1980’s

  • Numbers in times of day:

    • 8:00 A.M. or eight o’clock in the morning

  • Numbers in addresses:

    • 16 Tenth Street

    • 350 West 114 Street

  • Identification Numbers

  • Room 8

  • Channel 18

  • Henry VIII

Use words for the following:

  • Numbers beginning sentences

    • Two thousand four was an election year.

  • Centuries and decades (in lower case)

  • the eighties, the twentieth century

For American Psychological Association (APA)

The general rule governing APA Style on the use of numbers is to use numerals to express numbers 10 and above and words to express numbers below 10 (five, 16). Some exceptions to these guideline are stated below (Publication Manual of the American Psychological Association 2010).

Use numbers:

  • For all numerals 10 and above:

    • 21

    • 46

    • 11

  • To express decimals:

    • .23 cm

    • x=0.77

    • .48 s

  • In an abstract of a paper or graphical display.

  • Numerals immediately preceding a unit of measure:

    • 5-mg dose

    • 10.2 cm

  • Representations of mathematical information, ratios, percentages, etc:

    • multiplied by 5

    • 3 times as many

    • 5%

    • 16:1

    • 5th percentile

  • Representations of time, date, score:

    • 1 hr 34 min

    • 12:30 a.m.

    • 2-years-old

    • Exception: use words for approximations such as “about three months ago.”

Use Words:

  • Numbers that begin a sentence:

    • Forty-eight percent of the sample body…

  • Common fractions:

    • one fifth of the class

    • two-thirds majority

  • Universally accepted usage:

    • the Twelve Apostles

    • Five Pillars of Islam

Use Both:

  • Back to Back modifiers:

    • 2 two-way interactions

    • ten 7-point scales

    • Exception: Some items may be unclear when using this form, such as:

Unclear: 1st two items

Clear: first two items

Copyright (C)2013 by Charity Winsor-Farmer. All rights reserved.This document may be distributed as long as it is done entirely with all attributions to organizations and authors. Commercial distribution is strictly prohibited. Portions of this document may be copyrighted by other organizations.