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How to Write Percents

We answer questions such as "Should you use the word or symbol?" and "Is 'percent' singular or plural?"

By
Mignon Fogarty
5-minute read

First let's get our terminology right. In some cases "percent" and "percentage" can be interchangeable, but the easiest way to choose the right word for the right situation is to use "percent" with a number and "percentage" without a number. Examples:

"Percentage" without a number: What percentage of the chocolate was missing? 

"Percent" with a number: Forty percent of the chocolate was missing 

'Percent' Versus 'Per Cent'

In American English, when you write out the word "percent," it's one word.

It's more common to see the two-word version — "per cent" — in British English. The one-word version is definitely gaining ground in Britain, but the two-word form is still more common

A Google Ngram chart showing that the two-word version, "per cent," is more common than the one-word version in British English

The evolution of the word is kind of interesting. It started out as the two-word Latin phrase "per centum," which means "by the hundred," and over the years got shortened to the two-word English version with a period after "cent" to show that it was an abbreviation of "centum," then appeared as two words without a period, and is now quite established as a single English word.

Singular or Plural?

Sometimes people ask whether percentages are singular or plural, and as is so often the case, the answer is "It depends." If you're referring to a percentage of something, then that something determines whether you use a singular or plural verb. (In technical terms, that "something" is called the object of the preposition. The preposition is the word "of.") Here are two examples:

"Forty percent of the chocolate is missing." (In that sentence, "the chocolate" is singular so you use a singular verb: "is.") 

"Forty percent of the chocolate chips are missing." (In that sentence, "the chocolate chips" is plural so you use a plural verb: "are.") 

But what if there's no preposition or object of the preposition after the word "percent"? You've lost your clue! First, ask yourself if it's implied. If the implied phrase is singular use a singular verb, and if it's plural use a plural verb. Here's an example where the plural is implied:

The chocolate chips were pillaged. Forty percent were missing. (In the second sentence, the plural phrase — "the chocolate chips" — is the implied object of the preposition, so you use the plural verb — "were.")

In the next example, the implied object is singular so you use a singular verb:

The chocolate was pillaged. Forty percent was missing.

Finally, if you have no way to figure out whether the word "percent" is referring to something singular or plural, you can use whatever verb you like  singular or plural — it's that easy.

Using the Word 'Percentage'

It's a little more complicated with the word "percentage." The same rules I just told you apply when you are talking about a percentage of something: singular something, singular verb; plural something, plural verb. 

But when you are talking about the percentage of something, it's always singular.

A percentage of the chocolate chips were missing.

The percentage of chocolate chips missing was shocking.

Also, for "percentage," the order of the sentence matters. If the "percentage" phrase comes later in the sentence, after the verb, you need a singular verb.

A percentage of the chocolate chips were missing.

There is a large percentage of chocolate chips missing.

Words or Symbols?

Now that you know how to use percents, let's talk about how to write percents in a sentence. Style guides disagree about when you should use the word "percent" or the symbol and when you should use the numeral or the word for the number.

In general, I like the style where you always use the numeral and the percent symbol. The Associated Press Stylebook makes that recommendation (which is a recent change), and the Chicago Manual of Style says it's allowed, but that writing out the word "percent" is more common in nontechnical contexts.

The MLA Handbook has an even different rule: It says to spell it all out if you can do so in three words or less, but to use the numeral and percent symbol if it would take more words. So in MLA style, you'd write out "one hundred percent" with all the words, but you'd use numerals and the percent symbol for "48.5%."

As you can tell, the styles are all over the place, so be sure to check your style guide if you are required to follow one, and if not, decide on a style you like for yourself and just be consistent.

All three styles do agree, though, that you should write out the words if you use the percent at the beginning of a sentence. 

Decimals

Next, let's talk about small numbers.

If you're talking about a percent that is less than one, make sure you put a zero before the decimal point. Write something like 0.2%, not just .2%. This is true for writing any numeral that is less than one whether it's a percent or not. That little decimal point is too easy to miss without the zero in front of it.

Lies, D*** Lies, and Percentages

Finally, there are a few things you should know about calculating and interpreting percentages.

First, something can't decrease by more than 100%. Once 100% of something is gone, there isn't anything left, so don't write that a price or anything else decreased by 150%, for example.

Second, there's a difference between a percent change and a percentage point change. Going from 5% of something to 10% of something is a 100% increase, but only a 5 percentage point increase. Be careful not to call that a 5% increase because that's a common error.

And third, when you are reading about medical, political, or financial news, it is important to understand that big percentage changes can mean small overall increases or decreases. For example, an article that reports a 50% increase in the rate of a rare disease may be telling you that instead of 1 in 100,000 people getting floogety flork disease every year, now 1.5 people in 100,000 get the disease every year. A 50% increase sounds a lot scarier than the increase in raw numbers. Percentages aren't always misleading, but they can be, so your "could this be misleading" detector should be amped up when you start reading or hearing about percentages.


Additional Sources

Aaron, J. The Little, Brown Essential Handbook. New York: Pearson Education, 2006, p. 101.

Brians, P. "percent, per-cent," Common Errors in English Usage, http://www.wsu.edu/~brians/errors/percent1.html (accessed April 5, 2022).

Burchfield, R.W., ed. The New Fowler's Modern English UsageThird edition. New York: Oxford, 1996, p. 535.

Garner, B. "percent; per cent.; per cent; per centum," Garner's Modern English Usage, 4th edition. Oxford: Oxford University Press, 2016.

Garner, B. "percentage," Garner's Modern English Usage, 4th edition. Oxford: Oxford University Press, 2016.

Lutz, G. and Stevenson, D. Grammar Desk Reference. Cincinnati: Writer's Digest Books, 2005, p. 321.

"percent." Dictionary.com. http://dictionary.reference.com/browse/percent (accessed April 6, 2022).

"percentage." Dictionary.com. http://dictionary.reference.com/browse/percentage (accessed April 6, 2022).

"Percentages," Chicago Manual of Style, 17th edition. 9.18, 2017. https://www.chicagomanualofstyle.org/book/ed17/part2/ch09/psec018.html (accessed April 5, 2022).

"percent, percentage, percentage points." AP Stylebook. https://www.apstylebook.com/ap_stylebook/percent-percentage-percentage-points (accessed April 5, 2022).

"Percent versus percentage," Chicago Manual of Style, 17th edition. 3.82, 2017. https://www.chicagomanualofstyle.org/book/ed17/part1/ch03/psec082.html (accessed April 5, 2022).

About the Author

Mignon Fogarty

Mignon Fogarty is the founder of Quick and Dirty Tips and the author of seven books on language, including the New York Times bestseller "Grammar Girl's Quick and Dirty Tips for Better Writing." She is an inductee in the Podcasting Hall of Fame, and the show is a five-time winner of Best Education Podcast in the Podcast Awards. She has appeared as a guest expert on the Oprah Winfrey Show and the Today Show. Her popular LinkedIn Learning courses help people write better to communicate better.