Rules About Treatment of Numbers

By Mark Nichol

The basic rule about referring to numbers, according to The Chicago Manual of Style, is to spell them out when the total is one hundred or less and use numerals for larger numbers (the Associated Press Stylebook and some other style handbooks set the cut-off point after nine), but there are many exceptions. This post outlines those exceptions.

When referring to categorically similar totals, spell the pertinent numbers out if all totals are one hundred or less (for example, “sixty-five chairs arranged around twelve tables”) but use numerals if one or more totals are one hundred or less and one or more totals are more than one hundred (for example, “127 chairs arranged around 20 tables”). This rule applies only to two or more such numbers in proximity; previous or subsequent isolated numbers pertaining to the same category need not adhere. (Nor do unrelated numbers.) However, text with a concentration of statistics—whether an entire piece of content or one section—will likely benefit from the use of numerals in place of spelled-out numbers.

When totals appear in direct discourse (as when a speaker is quoted), spell out numbers, with the exception of years and elements of proper names; again, however, a concentration of numbers is perhaps best treated by using numerals. When reproducing quoted written material, however, do not alter number style.

Spell out large round numbers that include orders of magnitude (hundred, thousand, etc.).

Recast a sentence that begins with a numeral: For example, revise “2020 is the next leap year” to “The next leap year is 2020.” If the sentence must begin with a number, spell it out. In such cases, omit and in expressions such as “five thousand and three hundred.”

When a number consists of or includes a fraction, spell it out or use numerals according to the guidelines above, but numbers with decimals should be styled as numerals.

These rules also apply to quantities such as units of time or distance; exceptions can be made for such categories as temperature, clothing sizes, and miles per gallon.

Style quantities expressed with an abbreviation or a symbol in numeral form, and use numerals when a range is separated by an en dash (for example, “25–50 participants”). Refer to percentages with numerals. (However, spell out the word percent in nontechnical usage; use the symbol in statistical references.)

When referring to small amounts of money, spell out casual, isolated references but treat concentrations of such figures with the same guidelines as those for statistical materials. In addition, generally, express sums of more than one hundred dollars with numerals or with a combination of figures and words, such as in “$500 million budget”).

Related post: 10 Rules for Writing Numbers and Numerals

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8 Responses to “Rules About Treatment of Numbers”

  • Mirel

    First I’d like to thank you. I enjoy receiving your tips in my mailbox. I am familiar with these rules; however, I was recently told that in works of fiction, the tendency is to spell out most numbers, regardless of CMoS recommendations.

    Are there separate rules for fiction? If so, any insights for us?


  • Frank Butler

    Love your daily articles! My comments is that the word “numeral” as I understand it is defined as a symbol that represents a number. This includes both “three” and “3”, as explained correctly in the related post: “10 Rules for Writing Numbers and Numerals.” In this article, “numeral” seems to be used to refer to the subset of numerals consisting of digits with associated punctuation (such as a minus sign or a decimal point). I think the proper term for this is “Arabic numerals” or maybe “figures” (also used in the related post above.) Misusing the term “numeral” like this makes the article a bit confusing.

  • Ken Devine

    When it comes to rules about numbers, I think AP is much more user-friendly and comprehensible than CMoS.

  • Dale A. Wood

    In reply to Frank Butler: You are most certainly correct about the differences among “number”, “numeral”, and other words. For example, in “Seventy-seven trombones” and “77 trombones”, we have a case in which there are numbers in both expressions, but only 77 is a numeral. “Arabic numeral” is completely correct for 77, and the “Roman numeral” is LXXVII, and for 1977, it is MCMLXXVII.

  • Dale A. Wood

    It was quite unhandy in some early written languages such Greek in which the same symbols were used for either letters or numbers, just depending on the context. Also, the Ancient Greeks did not have lower-case letters: those were developed in medieval times. Thus (sigma)MAAZ was how they wrote Greece, but in different context, that might be a number.

  • Dale A. Wood

    ΣΜΑΑΖ = “Greece” in Roman type.

  • Dale A. Wood

    Of course, the Associate Press would be liberal is allowing the used of numerals (or “numerics”) in print (especially in newspapers!) because of their compactness – in paper and in ink.
    I think that it is important not to just make arbitrary statements, but rather to explain.
    “Nineteen Hundred Eighty-four” takes up a lot more resources than does “1984”.
    In contrast, in library catalogs, etc., “Nineteen Hundred Eighty-four” and “One Hundred One Dalmatians” go very nicely in ALPHABETICAL ORDER with the other titles.
    “One Million Years B.C.” and “Two Thousand One: A Space Odyssey” do, too.
    Something like the Chicago Manual of Style could contain things that are completely arbitrary unless genuine reasons were not given. Are they?
    On the other hand, the AP Handbook DOES say things on arbitrary bases, and I complain about this.
    I feel rather like Perry Mason in court:
    Perry: Your honor, I object!
    His honor: Objection overruled.
    Perry: May the record read that you decision is completely arbitrary.
    His honor: So noted!

  • Andy Knoedler

    While Mr. Wood is obviously trying to explain matters, he manages to obfuscate at the same time. The correct film titles are “One Hundred and One Dalmatians” and “2001: A Space Odyssey.” The expression of these titles — as numerals or spelled out — might have been an issue 50 years ago when they were marketed, but it’s no longer up for discussion.

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