Writing Numbers
The Blue Book of Grammar and Punctuation
Writing Numbers
Except for a few basic rules, spelling out numbers vs. using figures (also called numerals) is largely a matter of writers' preference. Again, consistency is the key.
Policies and philosophies vary from medium to medium. America's two most influential style and usage guides have different approaches: The Associated Press Stylebook recommends spelling out the numbers zero through nine and using numerals thereafter—until one million is reached. Here are four examples of how to write numbers above 999,999 in AP style: 1 million; 20 million; 20,040,086; 2.7 trillion.
The Chicago Manual of Style recommends spelling out the numbers zero through one hundred and using figures thereafter—except for whole numbers used in combination with hundred, thousand, hundred thousand, million, billion, and beyond (e.g., two hundred; twenty-eight thousand; three hundred thousand; one million). In Chicago style, as opposed to AP style, we would write four hundred, eight thousand, and twenty million with no numerals—but like AP, Chicago style would require numerals for 401; 8,012; and 20,040,086.
This is a complex topic, with many exceptions, and there is no consistency we can rely on among blogs, books, newspapers, and magazines. This chapter will confine itself to rules that all media seem to agree on.
Rule 1. Spell out all numbers beginning a sentence.
Examples:
Twenty-three hundred sixty-one victims were hospitalized.
Twenty twenty was quite a year.
Note: The Associated Press Stylebook makes an exception for years.
Example: 2020 was quite a year.
Rule 2a. Hyphenate all compound numbers from twenty-one through ninety-nine.
Examples:
Forty-three people were injured in the train wreck.
Twenty-seven of them were hospitalized.
Rule 2b. Hyphenate all written-out fractions.
Examples:
We recovered about two-thirds of the stolen cash.
One-half is slightly less than five-eighths.
However, do not hyphenate terms like a third or a half.
Rule 3a. With figures of four or more digits, use commas. Count three spaces to the left to place the first comma. Continue placing commas after every three digits. Important: Do not include decimal points when doing the counting.
Examples:
1,054 people
$2,417,592.21
Note: Some choose not to use commas with four-digit numbers, but this practice is not recommended.
Rule 3b. It is not necessary to use a decimal point or a dollar sign when writing out sums of less than a dollar.
Not Advised: He had only $0.60.
Better:
He had only sixty cents.
OR
He had only 60 cents.
Rule 3c. Do not add the word "dollars" to figures preceded by a dollar sign.
Incorrect: I have $1,250 dollars in my checking account.
Correct: I have $1,250 in my checking account.
Rule 4a. For clarity, use noon and midnight rather than 12:00 PM and 12:00 AM.
NOTE
AM and PM are also written A.M. and P.M., a.m. and p.m., and am and pm. Some put a space between the time and AM or PM.
Examples:
8 AM
3:09 P.M.
11:20 p.m.
Others write times using no space before AM or PM.
Example:
8AM
3:09P.M.
11:20p.m.
For the top of the hour, some write 9:00 PM, whereas others drop the :00 and write 9 PM (or 9 p.m., 9pm, etc.).
Rule 4b. Using numerals for the time of day has become widely accepted.
Examples:
The flight leaves at 6:22 a.m.
Please arrive by 12:30 sharp.
However, some writers prefer to spell out the time, particularly when using o'clock.
Examples:
She takes the four thirty-five train.
The baby wakes up at five o'clock in the morning.
Rule 5. Mixed fractions are often expressed in figures unless they begin a sentence.
Examples:
We expect a 5 1/2 percent wage increase.
Five and one-half percent was the expected wage increase.
Rule 6. The simplest way to express large numbers is usually best.
Example: twenty-three hundred (simpler than two thousand three hundred)
Large round numbers are often spelled out, but be consistent within a sentence.
Consistent: You can earn from one million to five million dollars.
Inconsistent: You can earn from one million dollars to 5 million dollars.
Inconsistent: You can earn from $1 million to five million dollars.
Rule 7. Write decimals using figures. As a courtesy to readers, many writers put a zero in front of the decimal point.
Example: A meter is about 1.1 yards.
As a courtesy to readers, many writers put a zero in front of the decimal point with numbers less than one.
Examples:
The plant grew 0.79 inches last year.
The plant grew only 0.07 inches this year.
(Note: For clarity, when needing the symbols for inches or feet, we recommend using the double-prime [″] or the prime [′], respectively, rather than double or single quotation marks.)
Rule 8a. When writing out a number of three or more digits, the word and is not necessary. However, use the word and to express any decimal points that may accompany these numbers.
Examples:
five thousand two hundred eighty feet
one thousand one hundred fifty-four dollars
one thousand one hundred fifty-four dollars and sixty-one cents
Simpler: eleven hundred fifty-four dollars and sixty-one cents
Rule 8b. When writing out numbers above 999, do not use commas.
Incorrect: one thousand, one hundred fifty-four dollars, and sixty-one cents
Correct: one thousand one hundred fifty-four dollars and sixty-one cents
Rule 9. When it's important to ensure a number is not misinterpreted, some writers will indicate the number in both numerals and written out. The number in parentheses comes second.
Examples:
Incorrect: Add (73) seventy-three grams of sodium chloride to the beaker.
Incorrect: Add (seventy-three) 73 grams of sodium chloride to the beaker.
Correct: Add 73 (seventy-three) grams of sodium chloride to the beaker.
Correct: Add seventy-three (73) grams of sodium chloride to the beaker.
Rule 10. The following examples are typical when using figures to express dates.
Examples:
the 30th of June, 1934
June 30, 1934 (no -th necessary)
Rule 11a. When spelling out decades, do not capitalize them.
Example: During the eighties and nineties, the U.S. economy grew.
Rule 11b. When expressing decades using figures, it is simpler to put an apostrophe before the incomplete numeral and no apostrophe between the number and the s.
Preferred: During the '80s and '90s, the U.S. economy grew.
Awkward: During the 80s and 90s, the U.S. economy grew.
Though not as common, some writers place an apostrophe after the number:
Example: During the 80's and 90's, the U.S. economy grew.
Awkward: During the '80's and '90's, the U.S. economy grew.
Rule 11c. You may also express decades in complete numerals. Again, it is cleaner to avoid an apostrophe between the year and the s.
Example: During the 1980s and 1990s, the U.S. economy grew.
Rule 12. Single-digit numbers are usually spelled out, but when they aren't, you are just as likely to see 2s and 3s as 2's and 3's. With double digits and above, many (but not everyone) regard the apostrophe as superfluous: I scored in the high 90s.
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