Numbers, Dates, and Time
Numbers
General Rule: Spell out whole numbers from zero through one hundred (e.g., three, ten, eighty-five) and whole numbers one through one hundred followed by hundred, thousand, or hundred thousand (e.g., one hundred thousand). Otherwise, use numerals. See The Chicago Manual of Style, 9.2, for additional detail.
Examples:
- Thirty-two children from eleven schools joined our art workshop.
- According to recent research, this painting is 103 years old.
- The three new parking lots will provide space for one thousand more cars.
- Our weekly visitor count now stands at 5,893.
Centuries: Particular centuries referred to as such are spelled out and lowercased: twentieth century, not 20th century, 20th Century, or Twentieth Century. Hyphenate when used as an adjective, but not when used as a noun: “He believes that twentieth-century technology should stay in the twentieth century.”
Exception: Use numerals when providing an approximate date for a collection object: 1st century BCE–2nd century CE
Dates and Time
- The app formats dates entered into CMS date fields in the US style (December 22, 2022), but in running text you may use US style or British style (22 December 2022), as long as there is consistency within running text.
- Months: Spell out all months using either style.
- In running text, make sure to add a comma after the year for US-style dates: “On December 22, 2022, she went to the Metropolitan Museum of Art.”
- Decades: Refer to decades as the 1960s or the sixties, not the 1960’s. Use an apostrophe in place of the first two numbers only when referring to multiple decades: the 1950s and ’60s.
- Time: Include lowercase a.m. and p.m., preceded by a space: The gallery talk begins at 10:30 a.m. and the opening reception starts at 7:00 p.m.