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Number Usage

Date and time

  • Use month-day-year for dates.
    Example: July 4, 2006
  • For year only, use numerals: 1977
  • For full dates, use commas around the year
    Example: July 20, 1969, was a special day.
  • For month and year only, use [month] [year], with no commas around the year.
    Example: July 2006 was a busy month.
  • For decades or years, use figures without apostrophes.
    Example: 2000s, not 2000’s Use 1990s, not 1990’s. You can also abbreviate a decade with an apostrophe: ‘80s.
  • Years are the exception to the rule not to use a numeral to start a sentence:
    Example: 2015 was a very good year.
  • When referencing times of day, use a.m. and p.m., always in lowercase and including periods. Indicate time as 2 p.m. and include the time zone.
    Example: 2 p.m. ET.
  • Use Noon for 12 p.m.

Time Zones

Capitalize the full name of the time zone: Eastern Standard Time, Eastern Daylight Time, Central Standard Time, etc.

Lowercase all but the region in short forms: the Eastern time zone, Eastern time, Mountain time, etc.

Use ET, CT, etc., at first mention for zones within the continental United States, Canada, and Mexico only if you link the abbreviation with a clock reading: noon ET or 9 a.m. PT. (Do not set off the abbreviations with commas.)

Spell out all references to time zones outside of the contiguous United States: When it is noon ET, it’s 1 p.m. Atlantic Standard Time and 8 a.m. Alaska Standard Time.

As an exception to the spelled-out form, you can shorten Greenwich Mean Time as GMT on second use if you use it with a clock reading.

Time and date ranges

Use an en dash with a space on either side for time and date ranges.


  • July 5 – 8, 2020
  • July 30 – August 2, 2020
  • December 29, 2020 – January 14, 2021
  • December 8, 2021, from 3 – 5:30 p.m. ET
  • April 3, 2022, from noon – 2 p.m. PT
  • September 5, 2022, from 11 a.m. – 3 p.m. Atlantic Standard Time


Do not carry numbers beyond the second decimal.


Use dollar signs and comma separators. Use numerals for all sums of money. Do not include cents.

Example: Freight costs account for $10,300 of the budget in Georgia.


  • Spell out numbers one through nine, except in headers.
  • For numbers 10 and greater, use numerals.
  • If a number begins a sentence, spell it out as a word or revise the sentence.
  • Use numerals in a series.
    Example: Chapters 1, 24, and 67
  • If you write a number as a numeral, all other numbers in that sentence must also be numerals.
    Example: “There are 50 states, 6 territories, and 1 tribe …”
  • Use Roman numerals if the number is part of a legislative title (Title IX, Title X).
  • Use commas in numbers 1,000 and higher.

Percent sign

Do not use the word percent with numerals; use the percent sign (%), as follows:

  • The rate of mental illness among those ages 18 to 25 was 29.8%.
  • According to a 2011 report, 20% of American adults experienced mental illness in the past year.
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