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Divas on Writing: Numbers in Writing

How many of us think about numbers when we write a book? Not very many, I’d wager. But numbers do play a part in most books, whether it’s an address, street number, monetary terms, the time of day, etc. Numbers are a part of our lives, and so they are often a part of a novel.

The rules for numbers in a work of fiction are many and vary from one style guide to the next, so I’ll talk about the recommendations from the Chicago Manual of Style, 16th edition. The following are the most common uses of numbers I see when editing works of fiction, but this list is not meant to be all-inclusive.

CMoS General Rules

Chicago Manual of Style recommends the following:

  • Spell out numbers zero to one hundred.
  • Use a combination of numerals and spelling if confusion will result, such as Three girls wore size 6, five wore size 9, and two wore size 12.
  • Remain consistent within the class of number if combining numerals and spelling. In other words, all the quantities in the previous example are spelled out and the clothing sizes were rendered as numerals.
  • Numbers in WritingThese rules apply to the following:
    • Nontechnical physical qualities (six foot three, twenty-three miles, 105 years old)
    • Ordinals (See section on ordinals below.)
    • Very large numbers (thirty-five million, 750 trillion)
    • Currency (ninety-five dollars, twenty cents, and $3,000)
    • Street numbers (102nd Street, Fifth Avenue)

Alternate Rule: Spell out single-digit numbers zero through nine only. The AP Style Guide and others adhere to this alternate rule, but CMoS prefers the zero to one hundred rule.

Numbers in Dialogue

All numbers should be spelled out in dialogue, even the ones over one hundred, unless confusion will result. However, years, such as 2010 or 1938, and numbers in brand names, such as 7-Eleven and 3M, can be rendered as numerals.

Beginning a Sentence with a Number

If a sentence begins with a number, it is always spelled out, even if that sentence begins with a year. Sometimes it’s best to rewrite the sentence and avoid starting a sentence with a number.

Two thousand ten was the year I wrote my first book.

In 2010, I wrote my first book.

Numbers in Writing


Words like first, second, twelfth, eighty-first, and so forth are spelled out. For numbers above one hundred, the letters used in ordinals (st, rd and nd) should not appears as superscript.

Grandfather fought in the 142nd Airborne Division. (Not 142nd)

The shop is on 118th Street.  (Not 118th)

When using the nth degree, the n is set in italics.

As stated above, if confusion will result, a combination of spelling and numerals is acceptable as long as you are consistent within the class or use of the numbers.

The first used car lot had 107 cars, the second had 56, and the third had 39.

Train 9 has ninety-five passengers, Train 75 has forty-three, and Train 127 has eighty-one.

Time of Day

Times of day are spelled out when referring to them as even, half and quarter hours, and o’clock is spelled out as well. But numbers that emphasize exact times, including even, half and quarter hours, appear as numerals.

Numbers in WritingMargaret met John at the coffee shop at a half past twelve.

Kaden went to bed at eight-thirty that night.

Megan barely made the 6:35 a.m. train.

You are cordially invited to a reception on July 9, at 8:30 p.m.


Years are written as numerals unless they are at the beginning of a sentence. If the year is expressed as two digits by dropping the first two digits, an apostrophe precedes the number.

Mom graduated high school in ’56.

Note: If using curly quotes, the quote should curl away from the number or in the direction of the part of the word or number that was dropped.

When the month and day appear together, the day is expressed with a numeral. If the year appears with the month and day, it is a numeral as well. But a day that appears by itself is spelled out oftentimes as an ordinal.Numbers in Writing

Mary had her baby June 21, 2011 but she was due on the twenty-sixth. Her brother was born two years later on June 29.

Centuries are spelled out and in lowercase.

The Industrial Revolution in the U.S. happened in the nineteenth century.

Decades are spelled out and in lowercase as long as the century is clear, or they are expressed as a number. There is no apostrophe when using a s at the end of a decade, but an apostrophe should be placed before the decade if the century has been dropped.

Jackson went to high school in the eighties.

Boyd loved cars from the 1950s.

The Sexual Revolution started in the late ’60s.


Common terms that are easier to express as numerals are acceptable.

60-watt bulb, 25 mph, or size 32 waist

Baseball batting averages and gun calibers that use a decimal do so without the leading zero. Gun calibers using millimeters use numerals and the abbreviation mm with no space between the numeral and mm.

She preferred the .38 special but ultimately bought a 9mm handgun.

Babe Ruth’s batting average was .342.

When using numbers in your work of fiction, common sense should prevail in situations where there are large strings of numbers or situations of multiple uses of numbers to show quantities or other types of numbered information. It’s preferable to break a few of these rules to avoid confusion or if readability is an issue.

What other rules of numbers would you like to know? Please let us know. We’d be happy to help.

Now… go write something!

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