Numbers and Dates

Overview

Numbers and dates need to be written clearly so your reader doesn’t get confused. Sometimes you write them as words, other times as numerals. Following the rules makes your writing formal, consistent, and professional.

Writing small numbers

Numbers from one through nine are usually written as words in formal writing.

• Example: I have five books on my desk.

Writing larger numbers

Numbers 10 and above are usually written as numerals.

• Example: There are 25 students in our class.

Numbers at the beginning of a sentence

Always spell out numbers if they come at the start of a sentence.

• Example: Twenty students volunteered for the trip.

• Not preferred: 20 students volunteered for the trip.

Using consistency in the same sentence

When writing multiple numbers in one sentence, keep the style consistent.

• Example: We ordered 15 pizzas for twelve teachers and 150 students.

Dates in writing

In U.S. style, write the month first, then the day, then the year. Use commas to separate parts.

• Example: Our next meeting is on March 5, 2025.

Avoiding shortcuts with dates

Don’t shorten years with apostrophes in formal writing, and be clear with decades.

• Example: She was born in 2008.

• Example: Music from the 1990s is still popular.

Ordinal numbers in dates

Do not use “st,” “nd,” “rd,” or “th” after dates in formal writing.

• Example: Correct: The event is on April 1, 2024.

• Wrong: The event is on April 1st, 2024.

Numbers in addresses, time, and money

Use numerals for street numbers, clock times, and amounts of money.

• Example: He lives at 123 Main Street.

• Example: The game starts at 7:30 p.m.

• Example: Tickets cost $12.50 each.

Summary

Write out numbers one through nine, and use numerals for 10 and above. Spell out numbers at the beginning of sentences, and keep your style consistent. For dates, follow the month-day-year format, avoid adding “st” or “th,” and use numerals for addresses, times, and money. These rules make your writing professional and easy to read.