Numbers, Dates and Times

Numbers

Numbers used to indicate order (first, second, 10th, 25th, etc.) are called ordinal numbers. Spell out first through ninth. Likewise, spell out only cardinal numbers one through nine. Use figures for 10 and above and for number references in all tabular matter and in statistical forms.

Figures must also be used for:

• Academic courses (History 6)
• Addresses (but spell out numbered streets that are nine and under e.g., 5 Seventh Ave.)
• Ages
• Court decisions (The court ruled 5-4.)
• Credit hours
• Decimals (preferred over fractions), percentages, and fractions with numbers larger than one (3 ½ laps, but spell out fractions less than one, e.g., two-thirds)
• Dimensions (but spell out the words kilograms, feet, inches, etc.)
• Distances (She walked 9 miles.)
• GPAs
• Headlines
• Highway designations (Interstate 5)
• Mathematical usage (Divide by 3.)
• Measurements
• Monetary units (along with the dollar sign instead of spelling out dollars)
• Millions, billions, trillions
• Planes, ships, and spacecraft designations (Apollo 9)
• Political districts (3rd Congressional District)
• Rank (She was his No. 1 choice.)
• Speed (She could only get the speed up to 8 mph.)
• Sports scores
• Temperatures (except zero; it was 8 degrees below zero or minus 8)
• Times (except with 12 a.m. and 12 p.m. — use midnight and noon instead)
• Units of measure
• Votes
• Years (references to an academic year should follow a hyphenated format, with just two digits following the hyphen e.g., 2016-17)

Spell out numbers at the start of a sentence. Exception: Sentences that begin with a year, e.g., 1992 was a great year.

Use commas in numerals with more than three digits.

Georgia Tech style is to use periods — not hyphens — to separate the segments of telephone numbers:

• 404.894.2000

With expressions denoting time, do not include the zeroes in top-of-the-hour references: 9 a.m.-5 p.m. Use a colon to separate hours from minutes: 3:30 p.m., 9:30-11 a.m. There should always be a space between the numbers representing the time and the a.m. or p.m.

An inclusive range of years falling within the same century should be abbreviated as follows:

• Franklin D. Roosevelt was president during 1933-45.

But when the range includes a transition to a second century, then all numbers must be used.

• G. Wayne Clough was president of Georgia Tech from 1994 to 2008.

Dates

Do not use a comma between a month and year or season and year; commas are used in dates when a specific day is given. When a month is used with a specific date, abbreviate only Jan., Feb., Aug., Sept., Oct., Nov., and Dec. Spell out when using alone or with a year alone. When a phrase refers to a day, month, and year, set off the year with commas.

• July 2019 was the hottest month in recent history.
• Friday, Dec. 13, 1987, was the date recorded in the police statement.

Use a hyphen for date ranges. But, if the construction is such that from precedes the date, then using to instead of the hyphen is preferable. When a hyphen is used, do not insert a space before and after.

• The Campus Recreation Center will be closed for renovations from July 12 to August 12.

Note: Depending on the type of document/communication, the year should be omitted if the event is taking place in the current year.

• Parents are invited to join their students for FASET, May 2-5.

Time

Use the days of the week, not today, tonight, tomorrow, or yesterday, in print copy (Daily Digest excepted), using Monday, Tuesday, etc., for days of the week within seven days before or after the current date. Avoid such redundancies as last Tuesday or next Tuesday; the tense of the verb used usually provides adequate indication of which Tuesday is meant: He said he finished the job Tuesday. She will return Tuesday.

Use noon and midnight instead of 12 p.m. and 12 a.m. But if using the term midnight would create ambiguity about what day something is taking place, since some users’ understandings may vary, consider instead 11:59 p.m. Thursday or 12:01 a.m. Friday.