Dates should follow the American format: month–day–year. The month should be written using letters, while the day and year should be written numerically.
- Correct: April 14, 2000
- Incorrect: 14 April 2000, 04/14/2000
Use a comma between the day and the year. If the date is in the middle of a sentence, use a comma after the year.
- Correct: Their concert is on August 23, 2022, at Madison Square Garden.
- Incorrect: Their concert is on August 23 2022 at Madison Square Garden.
Do not use a comma for only a month and a year.
- Correct: Their concert is scheduled for August 2022.
- Incorrect: Their concert is scheduled for August, 2022.
Do not use ordinals (numbers which end in st, nd, rd, or th and define a thing's position in an ordering) in dates.
- Correct: The spaceship landed on June 2, 2058.
- Incorrect: The spaceship landed on June 2nd, 2058.
Capitalize the names of months and do not abbreviate them.
- Correct: February, April
- Incorrect: Feb, Apr, Feb., Apr.
Do not use periods in dates.
Do not spell out years in words even if they begin a sentence.
- Correct: 1956 is the year I was born.
- Incorrect: Nineteen fifty-six is the year I was born.
Do not spell out decades in words. Decades from the 20th century may be abbreviated to their last two digits.
- Correct: During the '50s and '60s, many people preferred jazz.
- During the 1950s and 1960s, many people preferred jazz.
- Incorrect: During the fifties and sixties, many people preferred jazz.
When writing decades, do not use an apostrophe between the number and s.
- Correct: 1980s
- Incorrect: 1980's
When you choose to abbreviate a 20th-century decade, use an apostrophe before the first digit.
- Correct: '80s
- Incorrect: 80s
While you are free to choose between the full and abbreviated version for 20th-century decades, you should maintain consistency within each sentence.
- Correct: In the '50s, she rose to fame, but in the '60s, her sister overtook her.
- Incorrect: In the 1950s, she rose to fame, but in the '60s, her sister overtook her.
Do not capitalize the names of centuries. Names of centuries should be written as an ordinal followed by the word century. For the first through ninth centuries, the ordinal should be spelt out in letters; for the 10th century onward, it should be written using digits.
- Correct: eight century, 20th century
- Incorrect: 8th century, twentieth century
When used as nouns, both decades and centuries should be preceded by the definite article, the. This is generally not the case when they are used as adjectives.
- Correct: The 1980s are my favorite decade of the 20th century.
- Out of all 20th-century music, '70s rock is my favorite.
- Incorrect: 1980s are my favorite decade of 20th century.
- Out of all 20th century music, the '70s rock is my favorite.