Number Formats


The preferred format is:

  • Use numerals when listing a time; 3 p.m., 3:30 p.m.
  • Include a.m. and p.m. notation with periods in lowercase letters. Avoid the redundant: 6 a.m. in the morning.
  • Spell out noon and midnight. Do not capitalize. Avoid the redundant: 12 noon or 12 midnight

Abbreviate these months when used with a specific date: January, February, August, September, October, November, December unless used in a formal invitation; (Spell out March, April, May, June and July in all references).

Correct: Sept. 10, Oct. 31, March 4

Incorrect: September 10

Spell out the month if it stands alone in running text.

When writing dates, use numerals only. Avoid the use of st, nd, rd, or th; e.g.:

  • Correct: The event is scheduled for Feb. 1.
  • Incorrect: The event is scheduled for Feb. 1st.


Spell out numbers one through nine. Use numerals for numbers 10 and above.

Use figures within a series if more than one number is more than 10.

Correct: 22 hours, 19 minutes, 6 seconds; 12 hats, 5 purses, and 16 pairs of shoes

The preferred formats for phone numbers are:

  • with the area code set off by parentheses; e.g.: (210) 829-6000
  • with the use of hyphens; e.g. 210-829-6000

Hours of the day; e.g., 7 p.m. or 7:30 p.m.

Amounts of money with dollar sign; e.g., $3 or $3.50

Always use numerals when referring to age.

Correct: 3-year-old Annie takes ballet. or Annie, 3, takes ballet.

When using numerals with suffixes (never with dates), always place the suffix in superscript format; e.g. 1st, 2nd, 3rd, 4th, etc.

Do not:

  • begin a sentence with numerals; instead spell out the number or rephrase sentence. (A year is the exception)
  • add a numeral in parentheses after it’s written in words; e.g., three copies, not three (3) copies