Posted: March 3, 2025

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Nearly all writers use numbers in their writing. We use numbers to count; in dates; in addresses; when expressing time; in percentages, decimals and fractions; with names; with organizations; with units of measure; as cross-references; and in lists. Numerals are most commonly used, as they are far easier to recognize quickly, but when are words used instead? Let’s go over the basics.

Note: Do not rely solely on grammar or spelling checkers to identify errors in your writing. Although a checker may flag possible mistakes, it cannot do much else. While I still recommend using these AI checkers while you’re writing, I insist that you also trust a qualified human being to copyedit any work that you are working toward publishing.

Standard Practice

Enumeration, or things that you’ve counted, are written in words up to a point. Most publishers will have their own styles; some spell out numbers to 100, some to 20, some only until 10. In academic writing, a general rule is to use numerals whenever a number requires more than two words to spell out.

• e.g. There are 366 days in a leap year instead of There are three hundred sixty-six days in a leap year.
• e.g. Twelve new students joined the class.
• e.g. My manuscript is seventy-four thousand words! (A hyphenated number is considered one word)

Exception: in parallel construction (if you have a list) you will either spell out all numbers or use numerals for all numbers.

• e.g. In total, there were 122 white flowers, 79 red flowers, and 3 pink flowers.

In most business writing, however, numerals are used for all numbers ten and above.

• e.g. three samples, 13 participants

In technical writing, use the above rule, but for exact measurements, numerals are also used for the numbers zero through nine.

• e.g. 2 litres
• e.g. 1 hour

For numbers over one million, use a combination of numerals and words.

• e.g. 26 million
• e.g. 3.55 billion

Note: Depending on your region, you may use a comma or a period to separate long numbers and to distinguish decimals.

• e.g. Canada: 26,126 (twenty-six thousand one hundred twenty-six); England: 26.126 (twenty-six point one two six)
• e.g. Canada: 26.126 (twenty-six point one two six); England: 26,126 (twenty-six thousand one hundred twenty-six)

Dates, Addresses, & More

Dates and years are always written in numerals

• e.g. June 19, 1968
• e.g. 1452 CE
• e.g. 1999
• e.g. 387 BCE

Addresses are exact and thus should be written in numerals

• e.g. 45860 First Ave, Chilliwack, BC V2P 7K1
• e.g. 4 Privet Drive, Little Whinging, Surrey

Pages, chapters, volumes, acts, scenes, and lines are written in numerals for ease of navigation

• e.g. Chapter 17, page 394
• e.g. Romeo and Juliet, act 3, scene 2

Percentages can be written either way, depending on what they’re being used for. Fractions are typically written in numerals, with the exception of halves. Decimals are rarely written in words, though it.

• e.g. 48% or 48 percent or forty-eight percent
• e.g. 3 ½ (often seen in recipes); Platform 9 ¾ (iconic); the baby weighed nine and a half pounds
• e.g. 24.52; twenty-four point five two or twenty-four and fifty-two hundredths

Scores and statistics are typically written in numerals.

• e.g. The German football team is winning 4 to 1.
• e.g. Sugar water for hummingbirds should be a ratio of 3 to 1 in the winter.
• e.g. a mean of 26

Exact amounts of money are written in numerals or a combination of numerals and words. The exception for this rule is round dollars or found cent amounts.

• e.g. $4.50
• e.g. $6.7 billion
• e.g. seventeen dollars
• e.g. eighty cents

Rates should always be written in numerals.

• e.g. He can type 60 words per minute.
• e.g. When starting out, the author received 8 fan letters per day.
• e.g. seventeen dollars
• e.g. eighty cents

Time of day can be written any number of ways, mostly depending on the writer’s preference. Always use words together with o’clock.

• e.g. 2:00 AM; 9:30 PM
• e.g. three o’clock in the afternoon not 3 o’clock
• e.g. military time is written 0600 and spoken as “zero six hundred” or “oh six hundred”

In a sequence, write using both numerals and words for clarity.

• e.g. They bought six 2-litre bottles of soda for the party.
• e.g. He’s found 230 four-leaf clovers in his lifetime.
• e.g. seventeen dollars
• e.g. eighty cents

Beginning of a Sentence

When a number falls at the beginning of a sentence, write it out in words for clarity. If the number is more than two words, reframe the sentence so that the number falls later.

• e.g. Seventy people came to the party instead of 70 people came to the party
• e.g. The population of Canada is 40 million people instead of 40 million people live in Canada.

For further information, see my other Grammar articles:

Sources:

Aaron, J.E. & Morrison, A. The Little, Brown Compact Handbook, 5th Canadian ed. Pearson, 2013, chap 5