Episode Transcript

How to Write Percents
Episode 101: April 04, 2008

Grammar Girl here.

Today's topic is part II of the series on numbers: percentages and decimal points.
 
But first, it's free audiobook time again compliments of Audible.com, the Internet's leading provider of spoken word entertainment. Get a FREE audiobook download of your choice when you sign up today. For details, log on to audible.com/grammar.

Percent Versus Percentage

First let's get our terminology right. In some cases percent and percentage can be interchangeable (1), 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. For example, 

[Percent with a number] Forty percent of the chocolate was missing.
[Percentage without a number] What percentage of the chocolate was missing?
Percent Versus Per Cent

Also, 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, but sources tell me the one-word version is becoming more common in Britain too (2, 3, 4). The evolution of the word is kind of interesting. It started out as the Latin phrase per centum, which means "by the hundred (1)," and over the years got shortened to the two-word English version, and is now quite established as a single English word (2).

Singular or Plural?

Now, earlier this afternoon Shaun Klein asked me on Twitter 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's an example:
 

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

 

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:
 
The chocolate chips were pillaged. [new sentence] 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 (5).
 
Web Bonus

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, then it is always singular (6).
 
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, you need a singular verb (2).
 
A percentage of the chocolate chips were missing.
There is a large percentage of chocolate chips missing.

Words or Symbols

So now that you know how to use percents, let's talk about how to write percents in a sentence. Unlike what I told you last week for the general rules about writing numbers, for percentages it's better to use the numeral and not the word, even if it's a number less than 10. If you're writing about the 5% of chocolate chips that were damaged, use the numeral 5 and not the word five. The only time you would write out the word instead of using the number is if the number was at the beginning of the sentence. Then the rule about not starting a sentence with a numeral takes precedence and you write out the word (7, 8,9). [Note, some style guides disagree and say you can use the word or the numeral when writing out percents (10).]

Next you have to decide whether to use percent the word or percent the symbol. This is kind of like the general rule about writing numbers. If you're writing a technical or scientific document, then most sources recommend that you use the symbol. If you are writing something where numbers are used less frequently, then it is more common to write the word percent. Ultimately, it's a style issue, so make a decision and stick with it. Just remember to use the numeral and not the word for the number.

Decimals

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 (10, 11). 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 couple of 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. Never write that a price or anything else decreased by 150%. It's impossible*.

Second, when you are reading about medical, political, or financial news it is important to understand that big percentages 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 it's something to watch out for.

I know I said I'd cover writing numbers over a million and the use of hyphens, but I'm out of time. I'll put the answers in the e-mail newsletter early next week, so make sure you're subscribed. It's the blue button in the left-hand sidebar at quickanddirtytips.com. [Or subscribe to the newsletter here.]

Book Winners

Now it's free book time! First I have three signed copies of Scott Sigler's new book, Infected, for three lucky winners who are subscribed to my e-mail newsletter: Chris, Christy, and Monica all get a copy of Infected, which hit number one on Amazon's horror list this week. Thanks to Scott for providing the books. His info is at scottsigler.com.

Free Audiobook from Audible.com

And if you didn't win, you can still get a free copy of some other audiobook, because this week's Grammar Girl is brought to you by Audible.com--the leading provider in spoken word entertainment. Audible has over 35,000 titles to choose from to be downloaded and played back anywhere--just like this podcast. With the craziness in the financial markets lately I've been thinking about an audiobook I listened to a while ago by Terry Pratchett called Making Money. It's about how the banking system gets set up in a fantasy world, and it's funny and insightful at the same time. So log on to audible.com/grammar to get a FREE download of Making Money or an audiobook download of your choice when you sign up today.  I shouldn't have to tell you this, but grammar is spelled with an a: g-r-a-m-m-A-r. Again, for your free audiobook, go to audible.com/grammar.

Questions and comments for me go to feedback@quickanddirtytips.com or the voicemail line at 206-338-GIRL. There's a Web bonus this week about the word percentage, and you can read it in the full transcript of this podcast at www.quickanddirtytips.com, where you can find the other great shows including Money Girl, The Mighty Mommy, and The Get-It-Done Guy.

That's all. Thanks for listening.

References



1. percent. Dictionary.com. Dictionary.com Unabridged (v 1.1). Random House, Inc., http://dictionary.reference.com/browse/percent (accessed April 3, 2008).
2. Garner, B. Garner's Modern American Usage. Oxford: Oxford University Press, 2003, p. 598.
3. Wikipedia Contributors. ed. Nygaard, G. Wikipedia: Manual of Style, http://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style_(spelling) (accessed April 3, 2008).
4. Brians, P. "percent, per-cent," Common Errors in English Usage, http://www.wsu.edu/~brians/errors/percent1.html (accessed April 3, 2008).
5. percent. The American Heritage Book of English Usage. Houghton Mifflin Company, 1996, http://www.bartleby.com/64/C003/0227.html (accessed April 3, 2008).
6. percentage. Dictionary.com. The American Heritage® Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company, 2004, http://dictionary.reference.com/browse/percentage (accessed April 3, 2008).
7. "Numbers," The Chicago Manual of Style, Chicago: The University of Chicago Press, 2006, section 9 (accessed March 25, 2008).
8. Aaron, J. The Little, Brown Essential Handbook. New York: Pearson Education, 2006, p. 101.
9. Goldstein, N., ed. The Associated Press Stylebook and Libel Manual. Reading: Perseus Books, 1998, p. 156.
10. Lutz, G. and Stevenson, D. Grammar Desk Reference. Cincinnati: Writer's Digest Books, 2005, p. 321.
11. Burchfield, R.W., ed. The New Fowler's Modern English Usage. Third edition. New York: Oxford, 1996, p. 535.
 
 * Sigh. I should know better than to use absolute words like impossible. People have almost convinced me that when a value can become negative, it is possible for the value to decrease by more than 100%. What do you think? Join the discussion in the comments.

Comments (16) for How to Write Percents |  Subscribe to Comment

anjali Says:
4/13/2008 8:45:36 AM
i love it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Tarah Sweeney Says:
4/12/2008 1:30:11 AM
OMW. I absolutely LOVE your show. Thank you so much.
David Says:
4/11/2008 4:37:34 PM
Under "Lies, D*** Lies, and Percentages" one should mention percentage of a percentage. As in, "Today we cut the 30% increase by 50%!" is a sure sign someone is trying a lie-like spin.
Scott Dickinson Says:
4/10/2008 7:46:48 PM
Hey Grammar Girl, I think you made a mistake in your last comment: "Here's another example that is in the news a lot these days: by using leverage, a person can lose more than 100% of what they invested in their house; but the *price* of the house can't drop by more than 100%." Note that you placed a semi-colon after house and before but. Shouldn't that be a comma when a conjunction (but) is involved? Thanks ... Scott
Don Says:
4/8/2008 9:58:51 PM
PS: Grammar Girl, what’s with the new posting mechanism? It always loses the control characters. It doesn’t line break or paragraph… does this not make it much harder for you to read the posts? d
Don Says:
4/8/2008 9:56:54 PM
Grammar Girl, (et. al.): Well, there is no wonder there is confusion about this grammatically, there is also some confusion about this mathematically… I asked my two best sources that I know personally, a rocket scientist (really, my brother is a rocket scientist…) and my dad. I got two different answers. Dad agreed that things couldn’t decrease by more than 100%. My brother said that it could but that the percentage would be meaningless because he is used to dealing with percentages as absolute values. So I wrote a math professor that I found a website for. His answer was a nice, non-committal one which basically agreed with both positions. On my side, he agreed that if we took the difference between the two figures, we could accept that the change was a known quantity and that by doing the calculation of dividing the amount of the change by the point we started at we could reach a difference (decrease) of greater than 100%. He went on to add, however, that if you wanted to look at it another way, then the percentage for the change could not be calculated. If, the argument goes, you look at my bank balance as first falling to zero in the asset column and then going to 50 in the debt column, then all that could be said is that my balance first decreased by 100% and I then accrued a debt. The percentage beyond the zero (the change that was more than 100%) is incalculable since it would require that I divide the $50 accumulation of debt by the starting point of zero. As division by zero is undefined in this universe (where I assume all these changes are taking place after all), then it would be meaningless to try and assign a percentage change for that. So it all comes down to a semantics and style discussion. Thanks, Grammar Girl! I love the show because I often hear things that make me think! Keep up the good work and I hope to see you when you come to Denver! Don
Andrew Says:
4/7/2008 2:05:17 PM
I agree that something can decrease by more tha 100%... but it's d*** confusing. I would rewrite the sentence. (e.g., I spent so much money today that the $300 in my account only covered 67% of my bills. I overdrew!")
rpmason Says:
4/7/2008 9:46:48 AM
Regarding an item's value dropping more than 100% -- could that be the case when people pay a junk removal company to pick up an item? The item had value when they bought it but they paid someone to just take it away. :-)
Julie Says:
4/5/2008 6:36:58 PM
Don is correct. Since a percent means "a fraction with 100 as the denominator", there can be more than 100%. It is a math issue rather than a grammar issue in this case.
Grammar Girl Says:
4/4/2008 1:55:22 PM
Hi, Don. I think you're handling percentiles right, except that I usually hear them referred to with ordinal numbers instead of cardinal numbers: the fifth percentile (instead of the five percentile). Also, it's true that if you allow something to go negative, then it can decrease by more than 100%. Still, in the bank account example, I could argue that your *balance* decreased 100% and then you started accruing debt. Here's another example that is in the news a lot these days: by using leverage, a person can lose more than 100% of what they invested in their house; but the *price* of the house can't drop by more than 100%.
Grammar Girl Says:
4/4/2008 1:39:50 PM
Hi, Len. I agree that it seems a little strange that "a percentage of the chocolate chips" would take a plural verb, since "a percentage" is singular, but I double checked again this morning and I have two good sources that clearly say it would take a plural verb in the example I used in the show. Both "Garner's Modern American English" and the usage note in "The American Heritage Dictionary" say to use a plural verb when "a percentage" is followed by an "of" clause with a plural noun.
Grammar Girl Says:
4/4/2008 1:29:19 PM
Hi, Sam. Thanks for pointing out the problem with the references. I added an additional reference late last night and forgot to update the numbering. It's fixed.
SAM Says:
4/4/2008 12:39:19 PM
Your references cite two "4s."
aardvark Says:
4/4/2008 11:39:12 AM
Very good. Very clear. aardvark teaches his little aardvarks that when using the word percentage, make sure to notice the article in front of it. Is it "a" or is it "the"? The rules for "a number" (plural) and "the number" (singular) apply to the word percentage. The percentage of gainers was staggering. A percentage of gainers were discredited.
Don Says:
4/4/2008 11:31:59 AM
Dear Grammar Girl, I have two questions about today’s episode for you. The first is a question about how to write percentiles; does one treat them as if they were percentages? Since there is no sign for percentile, I would tend to use the style for writing numbers. “It is said that 70% of the scholarships in the United States are awarded to the students in the top five percentile of their respective classes.” It would look odd to say that the bottom 95 percentile of the student body get only 30% of the scholarships. The other question that occurred to me while listening to the podcast deals with your comment that you can never decrease something by more than 100%. Since things can increase by more than 100% it stands to reason that they can decrease by more than 100% as well. I’m sure that you would not argue that if widget production in the United States went from six million to fifteen million that it had increased by 250%. (Since 6 x 2.5 = 15, the increase was 250%.) Conversely, if my bank account was overdrawn by $150 this morning when I looked, but had had a balance of $300 yesterday, then it had decreased by 150% since I last checked it. The decrease was $450 which is 150% of the original balance… Since the balance is less than it was, then, the amount must have decreased. Since the decrease was more than the original value, then the percentage of the decrease must be more than 100%. I would agree that anything that cannot go from positive to negative (or vice versa) cannot decrease by more than 100%, but once you remove that restriction the rule no longer holds.
Len Says:
4/4/2008 7:50:19 AM
Please keep up the great work :-) I work in a technical writing and publishing department, and I must say that I really enjoy reading what you write. By the way, I'm English, now living in Belgium. Now... I disagree with your example today "A percentage of the chocolate chips were missing." because you are speaking about a percentage (singular) that is missing, not some percentages (plural) - eg, "some percentages are incorrect". It's easier to work out if you substitute handful for percentage: A handful of the chocolate chips were missing? No: A handful of the chocolate chips was missing. Or even drop the chocolate chips entirely: a percentage (or a handful) was missing. Hope to read many more good tips. Len

Add Comment

 *
 *
 *
  Image to deter spam submissions
  To deter spam submissions, please type the letters from the image into the box below:
 *
 
  Fields marked with "*" are required