Writing Style Guide - Dates and Numbers | University of Portland

Writing Style Guide - Dates and Numbers


Jan., Feb., Aug., Sept., Oct., Nov., and Dec. are appropriate abbreviations for months. Days of the week may also be abbreviated (Sun., Mon., Tues., Wed., Thurs., Fri., Sat., Sun.). Use no punctuation if listing only the month and the year, but set the year off with commas if listing the day of the month as well. The year should be offset with commas when it is preceded by month and day.

The basketball game is on Thursday, Feb. 16.
She was born on October 15, 1963, in Orlando.
The snowstorm was in Feb. 2011.


Ordinals are not used with month-date combinations         

Commencement will be held May 5 (not May 5th).
The basketball game is on Feb. 27 (not Feb. 27th).

Time Spans

When referencing a span of years, use a hyphen and drop the first two numbers of the second year. If the years span a century change, use all four numbers of the second year.          


To describe sequences of dates or inclusive dates, use a hyphen (with no spaces between the hyphen and the characters) instead of the word “to” or “through.”

The box office is open Monday-Friday.
The performance will run Sept. 14-22.

Use an “s” without an apostrophe after the year to indicate spans of decades or centuries. Use an apostrophe before the year for class years or abbreviations to indicate the first two numbers of the year are omitted. An apostrophe after the year is needed for possessives. It is important that the apostrophe points in the correct direction: down and to the left.

The University was founded in the early 1900s.
Shannon belonged to the class of 1978.
Shannon belonged to the class of ’78.
The presidential election was 1980’s biggest news story.


Use the dollar sign and numbers. Do not use a decimal and two zeros.


Use a comma in dollar amounts in the thousands.


For dollar amounts beyond thousands, use the dollar sign, numeral (even when less than 10), and appropriate word.

$21 million


In prose, spell out numbers one through nine and use numerals for numbers 10 and above.

The tree stood five feet high.
There are 26 teams in the old league, but only eight in the new one.

However, use numerals for numbers less than 10 to indicate age, statistics, sports scores, percentages, amounts of money, times of day, days of the month, measurements, and proportions.

The temperature stayed at 68 degrees.
She was 9 years old when she visited campus.

Spell out a number at the beginning of a sentence.

Forty engineering students came to the meeting.

When using a measurement term without numerals, always spell it out.




Telephone numbers

Include the area code as part of the complete number. Use periods between the area code and number. 

Please contact the Help Desk at 503.943.7000.


Abbreviations for the division of day (a.m. and p.m.) should be lowercase. When writing a time that falls on the hour, do not use “:00.” Use “noon” and “midnight,” never 12 p.m. or 12 a.m.

1 a.m.
2:30 p.m.

Time Spans

Use an en-dash (not a hyphen) without spaces to connect numbers to signify "up to and including."

Spring Break is March 6–13.
Class takes place 6:30–8 p.m.

But, do not use the en dash for time spans when "from" or "between" precedes the numbers:

She attended UP from 2011 to 2015.
The office is closed between 11:45 a.m. and 12:45 p.m. daily for lunch.