When are numbers expressed in words?

This page reflects guidance from the sixth edition of the Publication Manual.

For the most current guidelines, see the Publication Manual of the American Psychological Association (7th ed.) and our Style and Grammar Guidelines page for the seventh edition.

Use words to express

any number that begins a sentence, title, or text heading. Whenever possible, reword the sentence to avoid beginning with a number.

Examples:

  • Ten participants answered the questionnaire.
  • Forty-eight percent of the sample showed an increase; 2% showed no change.

common fractions

Examples:

  • one fifth of the class
  • two-thirds majority

universally accepted usage

Examples:

  • the Twelve Apostles
  • Five Pillars of Islam

(adapted from the sixth edition of the APA Publication Manual, © 2010)