The Grammarphobia Blog

The right percent

Q: I’m a journalism student at Mizzou and recently disagreed with an editor about the word “percentage.” I thought it was interchangeable with “percent,” but she wasn’t so sure. We checked the AP stylebook, but it didn’t illuminate anything. What’s the verdict?

A: These words aren’t necessarily interchangeable. A “percent” is a hundredth part of something, but a “percentage” can mean any part of a whole. 

This is why “percent” is generally used with a number: “50 percent of the flour was ruined.”

And this is why “percentage” is not used with a number, just an ordinary adjective: “a large percentage of the flour was ruined.”

Still, “percent” is sometimes used in place of “percentage,” as in “What percent of the flour was ruined?”

This usage has been discouraged by some language authorities, but it’s recognized in most standard dictionaries and seems idiomatic to us.

The Columbia Guide to Standard American English, by Kenneth G. Wilson, has this to say about the subject:

Percentage is the more widely accepted noun, especially in Edited English, but Informal use of percent (What percent of your time do you spend watching TV?) seems thoroughly established.”

So if that’s what you and the editor disagreed about, you can both relax. If you’re writing formal English, however, you might want to stick with “percentage.”

Now comes the sticky part.

“Percentage” is a noun. (The noun can also be used attributively as a modifier, as in “percentage point.”)

And “percent” is a noun when it means “percentage.” But there’s some disagreement about how to classify “percent” in other cases.

The Oxford English Dictionary, for example, classifies “per cent” (it’s two words in British English) as an adverb in almost all the other cases.

The dictionary describes “percent” as an adverb when it appears with a number to form a noun phrase that expresses a proportion in hundredths (for example, “10 percent of the students”).

That definition covers a lot of territory. Too much, in our opinion and in the opinion of some standard dictionaries.

Those dictionaries include The American Heritage Dictionary of the English Language (5th ed.), Webster’s Third New International Dictionary, Unabridged, and the online Macmillan Dictionary in both its US and UK editions. 

All standard dictionaries, including those three, would agree with the OED that “percent” is an adverb when it modifies a verb or an adjective.

In this adverbial Oxford citation, for example, it modifies a verb: “The Funds rose 1 per cent. on the news” (1804).

However,  American Heritage, Webster’s Third, and Macmillan would disagree with the OED that “percent” is an adverb in these Oxford citations:

“The Blank Tickets bear seven per Cent. Interest” (1710); “At the rate of ten per cent. therefore …” (1776); “Ninety per cent of the cooks do their full share” (1904); “cut my social life by about 35 per cent” (1973).

The three standard dictionaries would consider “percent” an adjective or a noun in those citations. We’ll quote some of their own examples of “percent” used as an adjective, a noun, and an adverb.

Adjective : “a 0.75 percent increase in interest rates” … “harvested 50 percent more wheat” … “another 100 percent result” … “a 3½ percent government bond” … “a 2.25 percent checking account.”

Noun: “provided 40 percent of Europe’s requirements” … “42 percent of the alumni contributed” … “owns 20 percent of the business” … “represent 50 percent of the workforce.”

Adverb: “agreed with her suggestions a hundred percent” … “sales increased 30 percent” … “if he is even one percent responsible for the accident.”  

Why does the OED call “percent” an adverb in cases where some standard dictionaries do not? This probably has a lot to do with the fact that “percent” started out as an adverbial phrase. 

The OED says “per cent” (it uses the British form) was modeled on the Italian phrase per cento, which can be translated as “for (every) hundred.”

The dictionary says the phrase appeared in Italian in 1263 or earlier. (In the following century, incidentally, the Italians invented the % sign.)

“Per cent” was first recorded in English in 1568, but a slightly earlier form showed up in 1565—“per centum,” abbreviated as “per cent.” with a period.

As the OED explains, “per centum” was “the usual form in Acts of Parliament and most legal documents.”

This coinage too was modeled after the Italian per cento, though it was fashioned out of Latin elements (per plus centum). In fact, per centum did not exist in Latin.

The facts remain that in Britain the word is still mostly written as a phrase—“per cent”—and is still regarded as adverbial in some standard dictionaries.

The Cambridge Dictionaries Online, for instance, says it’s an adverb in the examples “You got 20 percent of the answers right” and “Only 40 percent of people bothered to vote.”

American dictionaries would generally regard “percent” as a noun in those examples, though perceptions about the linguistic function of “percent” aren’t unanimous even in the United States.

The Chicago Manual of Style (16th ed.), for example, sort of agrees with Cambridge and sort of doesn’t.

“Despite changing usage,” the manual says, “Chicago continues to regard percent as an adverb (‘per, or out of, each hundred,’ as in 10 percent of the class)—or, less commonly, an adjective (a 10 percent raise).”

And by the way, the manual, which is widely used in the publishing industry (that means in formal, edited English), also recommends “percentage as the noun form (a significant percentage of her income).”

While we’re on the subject, many people use “percent” and “percentage point” incorrectly—the terms are not interchangeable.

For instance, if a mortgage rate falls to 6 percent from 8 percent, that’s a decline of 2 percentage points, or 25 percent. 

So beware. There’s no percentage in getting things wrong.

By the way, an old friend of ours from the New York Times graduated from the Missouri School of Journalism. Good look with your career!

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