Revised as of
27 Jan 2023
While a percent can be an adjective, adverb, or noun, in this Formatting Tip we’re concerned with whether the symbol (%) is used or if percent is spelled out.
A second concern is if an arabic figure is used or if the number is spelled out.
The rules depend upon the style guide you or your publisher is using, so this post breaks it up into when to use percent or its symbol and when to spell out the numbers or use arabic numbers. Which can make this headache-inducing.
There are a few basics you can (mostly) rely upon:
- Spell out the number and percent if it starts the sentence.
- In humanist (non-technical) writing, spell out the number and percent.
- To give the impression of quantity, use numbers; use your own judgement as to whether you use percent or %.
- In scientific, tabular, or statistical writing, use arabic numbers and %.
Otherwise, it’s a crapshoot — depending upon the style guide you use. Whatever style you choose, be consistent!
NOTE: Percentage is a noun and not interchangeable with percent. Do read the post “Percent vs Percentage vs Percentile” for further details.
Formatting Tips started . . .
. . . as my way of dealing with a professional frustration with words that should have been capitalized or italicized, in quotes or not, what should be spelled out and what can be abbreviated, proper styling for the Latin names of plants, the proper formatting and usage of titles and more in manuscripts I was editing as well as books I was reviewing. It evolved into a sharing of information with y’all. I’m hoping you’ll share with us any questions you’ve had on this subject that have been a bête noire for you from either end.
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| When to Spell Out Percent, or Use the Symbol | ||||||||
|---|---|---|---|---|---|---|---|---|
| Style Guide | Spell Percent Out | Use the Symbol | ||||||
| AMA Manual of Style | Rule: Anytime you spell out a number, spell out percent. And you always spell the number when it starts a sentence! | Rule: Use % with numerals. | ||||||
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Seventy-five percent of all neurosurgeons . . .
Five percent of operations . . . |
Some 75% of all neurosurgeons . . .
In 5% of operations . . . |
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| Rule: Repeat the symbol in an expression of range. | ||||||||
| From 15%–25% of residents reported falling ill.
From 15% to 25% of residents reported falling ill. |
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| Rule: If a percentage range begins a sentence, you should spell out both the number and percent . . . but it would be better to re-word the sentence so the percentage comparison is more obvious.
See above. |
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| Fifteen percent to 25% of residents reported falling ill. | ||||||||
| AP Stylebook | Rule: Always spell out percent because the symbol doesn’t translate between AP and newspaper computers. | Rule: As of April 2019, AP is allowing the use of %. | ||||||
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The professor said 60 percent was a failing grade.
He said 70 percent of the membership was there. |
The professor said 60% was a failing grade.
He said 70% of the membership was there. |
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| APA Style | Rule: If the number begins a sentence, title, or text heading, spell it out and use percent. | Rule: Use % with arabic numbers in all cases — except at the beginning of a sentence. | ||||||
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Seventy-five percent of all television viewers . . .
Five percent of banana eaters . . . |
It’s been said that 75% of all television viewers . . .
Some 12% of people interviewed . . . |
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| Rule: If the number is spelled out, use percent. | Rule: Use arabic numbers and % in tables and figures (to save space) no matter the size of the number. | |||||||
| If seventy-five percent of all television viewers . . . |
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| Rule: Use percent with numbers between zero and nine. | Rule: Use % with numbers from 10 and up. | |||||||
| If you eat five percent of the bananas . . . | If you eat 15% of the bananas. . . . | |||||||
| The Chicago Manual of Style | Rule: Spell out percent in nontechnical, humanist contexts UNLESS there are numerous percentage figures. | Rule: Use % (and arabic numbers) in scientific, tabular, or statistical copy. | ||||||
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10 percent
Ten percent (if it begins a sentence) Her five-year certificate of deposit carries an interest rate of 5.9 percent. Fewer than 5 percent of readers buy books at an actual bookstore. |
10%
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| Rule: Spell out percent at the end of an expressed range. | Rule: Repeat the symbol in an expression of range. | |||||||
| With 90–95 percent of the work complete, we can relax. | 35%–50%
a range of 30% to 40% |
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| MLA | Rule: Spell out the numbers and use percent in prose that does not use numbers extensively. | Rule: Use the % symbol with arabic numbers, especially in statistical copy that calls for frequent use of numbers. | ||||||
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Only four percent of those responding planned to continue to graduate school in Spanish or related disciplines. | “Japanese enrollments increased by 3.1%, from 66,771 in 2013 to 68,810 in 2016; Korean enrollments increased by 13.7%, from 12,256 in 2013 to 13,936 in 2016” ( Looney). | ||||||
| When to Spell Out the Numbers or Use Arabic Numbers | ||||||||
| Style Guide | Spell Numbers Out | Use an Arabic Figure | ||||||
| AP Stylebook | Rule: Spell out the number and use percent at the beginning of a sentence. | Rule: Uses an arabic number with percent unless the number begins a sentence. | ||||||
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Twenty percent of the ants were observed to react to the stimulus. | Anywhere from 20 to 22 percent of the ants were observed to react to the stimulus. | ||||||
| APA Style | Rule: Spell out any numbers between zero and nine and use percent. | Rule: Numbers greater than nine are expressed as arabic numbers and use %. | ||||||
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Only three to five percent of the work is complete, so we must work harder.
Twenty percent of the ants were observed to react to the stimulus. |
From 90% to 95% of the work is complete, so we can relax.
Some 20% of the ants were observed to react to the stimulus. |
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| The Chicago Manual of Style | Rule: Spell out the number and use percent at the beginning of a sentence. | Rule: Prefers the use of arabic numbers for all numbers (with percent) unless the number begins a sentence. | ||||||
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Ninety to ninety-five percent of the work is complete, so we can relax.
Twenty percent of the ants were observed to react to the stimulus. |
The treatment resulted in a 20–25 percent increase in reports of night blindness.
A 75 percent likelihood of winning is worth the effort. |
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C’mon, get it out of your system, bitch, whine, moan . . . which words are your pet peeves? Also, please note that I try to be as accurate as I can, but mistakes happen or I miss something. Email me if you find errors, so I can fix them . . . and we’ll all benefit!
Satisfy your curiosity about other Formatting Tips by exploring its homepage or more generally explore the index of self-editing posts. You may also want to explore Book Layout & Formatting Ideas, Formatting Tips, Grammar Explanations, Linguistics, Publishing Tips, the Properly Punctuated, Word Confusions, Writing Ideas and Resources, and Working Your Website.
Resources for Percent
Some of these links may be affiliate links, and I will earn a small percentage, if you should buy it. It does not affect the price you pay.
AMA Manual of Style. 10th Ed. Oxford University Press, 2007. 19.7.2. Print.
Lakin, C.S. “The 100 Percent Solution.” Live Write Thrive. 1 Mar 2013. Web. 14 Mar 2013. <https://www.livewritethrive.com/2013/03/01/the-100-percent-solution/>.
Looney, Dennis and Natalia Lusin. “Enrollments in Languages Other Than English in United States Institutions of Higher Education, Summer 2016 and Fall 2016: Preliminary Report.” Modern Language Association of America. Feb 2018. Web. 29 May 2021. <https://www.mla.org/content/download/83540/2197676/2016-Enrollments-Short-Report.pdf>.
Assorted style guides were consulted, including The Chicago Manual of Style, the AMA Manual of Style, the AP Stylebook, APA Style, and the MLA Handbook.
If you purchase a manual through one of these links, I will receive a small commission — which will not impact the cost to you.
Pinterest Photo Credits:
Percent by Pramit Marattha, <https://pixabay.com/users/pramit_marattha-3815284/>, is under the Pixabay License, via Pixabay.
