Cardinal Number

Glossary of Grammatical and Rhetorical Terms

Cardinal numbers
The little men in this cartoon are carrying cardinal numbers. In a composition, you would customarily write out these numbers as words: zero, one, two, three, four, five, six, seven, eight, and nine. Tungstenblue/Getty Images

A cardinal number is a number used in counting to indicate quantity. A cardinal number answers the question "How many?" Also called a counting number or a cardinal numeral. Contrast with ordinal number.

Though not all style guides agree, a common rule is that cardinal numbers one through nine are spelled out in an essay or article, while numbers 10 and above are written in figures. An alternative rule is to spell out numbers of one or two words (such as two and two million), and use figures for numbers that require more than two words to spell out (such as 214 and 1,412).

In either case, numbers that begin a sentence should be written out as words.

Regardless of which rule you choose to follow, exceptions are made for dates, decimals, fractions, percentages, scores, exact sums of money, and pages--all of which are generally written in figures. In business writing and technical writing, figures are used in nearly all cases.

Examples, Tips, and Observations

The cardinal numbers refer to the size of a group:
zero (0)
one (1)
two (2)
three (3)
four (4)
five (5)
six (6)
seven (7)
eight (8)
nine (9)
ten (10)
eleven (11)
twelve (12)
thirteen (13)
fourteen (14)
fifteen (15)
twenty (20)
twenty-one (21)
thirty (30)
forty (40)
fifty (50)
one hundred (100)
one thousand (1,000)
ten thousand (10,000)
one hundred thousand (100,000)
one million (1,000,000)

"At universities nationwide, employment of administrators jumped 60 percent from 1993 to 2009, 10 times the growth rate for tenured faculty."
(John Hechinger, "The Troubling Dean-to-Professor Ratio." Bloomberg Businessweek, November 26, 2012)

"One hundred students were selected at random from those enrolled at a large college."
(Roxy Peck, Statistics: Learning from Data. Cengage, Wadsworth, 2014)

The Difference Between Cardinal Numbers and Ordinal Numbers

"When using number words, it is important to keep the difference between cardinal numbers and ordinal numbers in mind.

Cardinal numbers are counting numbers. They express absolute number without any implication of position. . . .

"The ordinal numbers, on the other hand, are position numbers. They correspond to the cardinal numbers but indicate position in relation to other numbers. . . .

"When a cardinal number and an ordinal number modify the same noun, the ordinal number always precedes the cardinal number:

The first two operations were the most difficult to watch.

The second three innings were quite dull.

In the first example, the ordinal number first precedes the cardinal number two. Both first and two are determiners. In the second example, the ordinal number second precedes the cardinal number three. Both second and three are determiners."
(Michael Strumpf and Auriel Douglas, The Grammar Bible. Owl Books, 2004)

Using Commas With Cardinal Numbers

  • "Use a comma between the day of the week and the month, between the day of the month and the year, and between the year and the rest of the sentence, if any.
    The attacks on the morning of Tuesday, September 11, 2001, took the United States by surprise.
    Do not use commas with dates in inverted order [e.g., 23 April 2016]  or with dates consisting of only the month and the year [e.g., January 2017] . . . .

    "In numerals of five digits or more, use a comma between each group of three digits, starting from the right.
    The city's population rose to 158,000 in the 2000 census.

    The comma is optional within numerals of four digits but is never used in years with four digits."
    (Andrea Lunsford, The St. Martin's Handbook, 6th d. Bedford/St. Martin's, 2008)

    More Tips on Using Cardinal Numbers

    • When one number immediately follows another, spell out one and use figures for the other: three 100-meter events, 125 four-poster beds." (Diana Hacker, The Bedford Handbook, 6th ed. Bedford/St. Martin's, 2002)
    • "When citing inclusive page numbers in a bibliographic entry, give the complete numbers for any number between one and ninety-nine: 4-5, 12-17, 22-24, 78-93.
    • "You may shorten numbers over ninety-nine if they fall within the same range (e.g., 200-299, 300-399, 1400-1499) or if the second number will be clear to your reader when shortened. Numbers such as these are clear: 107-09, 245-47, 372-78, 1002-09, 1408-578, 1710-12."(Linda Smoak Schwartz, The Wadsworth Guide to MLA Documentation, MLA Update 2009, 2nd ed. Wadsworth, Cengage, 2011)
    • "Note that numbers used with o'clock, past, to, till, and until are generally written out as words: at seven o'clock​ twenty past one." (Toby Fulwiler and Alan R. Hayakawa, The Blair Handbook, 4th ed. Prentice Hall, 2003)