100 Things You Should Know About People: #54 — The Average Reading Level In the USA Is Grade 8

Picture of a kindle

If you are a biologist, then the paragraph below might make sense to you:

“The regulation of the TCA cycle is largely determined by substrate availability and product inhibition. NADH, a product of all of the deydrogenases in the TCA cycle, with the exception of succinate dehydrogenase, inhibits pyruvate dehydrogenase, isocitrate dehydrogenase, a-ketoglutarate dehydrogenase, while succinyl-CoA inhibits succinyl-CoA synthetase and citrate syntase.”

But if you are not a biologist, it might take you a long time to understand what that paragraph says. You can technically read the paragraph, but that doesn’t mean you understand it. In order to understand information you need one or both of the following:

You will understand new information more easily if there is already a framework of knowledge to fit it into.

The information needs to be at the appropriate reading level.

The Flesch-Kincaid Reading Score – The most common formula for calculating the readability of a particular passage of text is the Flesch-Kincaid method. The method gives you a Reading Ease formula and also a reading grade level score.

The formula to calculate how readable your text is:

Reading Score Formula
Flesch-Kincaid Reading Score Formula

The higher the score the easier the passage is to read. Low scores mean the passage is hard to read.

An online tool for calculating readability – Luckily, you don’t actually have to use the fomula. Some word processing software has the Flesch-Kincaid formula built in. Or you can use this online tool:


to calculate the reading level of a particular passage. The calculator gives you a Reading Ease Score as well as a Grade Level Score.

I decided to try out the calculator. First I used a paragraph from the State of Colorado Governor’s website:

Colorado State Governor's Web Site
Colorado State Governor's Web Site
Close Up Of the Colorado Governor's Web Page
Close Up Of the Colorado Governor's Web Page

This web page had  a reading level of Grade 12 and a reading ease score of 40. Americans average a reading level of Grade 8, so 12 is harder than the average American can read. For the reading ease score, higher is better. Comic books are at 90, and legal documents are often 10 and under.

Next I tried out the calculator on the State of Wyoming Governor’s home page:

Wyoming State Governor's Web Page
Wyoming State Governor's Web Page
Close Up Of Wyoming State Governor's Web Page
Close Up Of Wyoming State Governor's Web Page

Not much difference – a Grade level of 11 and a Reading Ease score of 42.

Feeling quite smug, I decided I would run one of my blog posts through the calculator:

Readability score for one of my blog posts
Readability Score For One Of My Blog Posts

Uh oh! Reading Grade level of 15 and Reading Ease score of 55?! The Reading Ease is not too bad, but Grade level 15 is a bit high. Well, I knew my readers were smart!

What do you think? Do you ever test the readability level of what you write online?

For those of you who like to read the research:

Stedman, L. and Kaestle, C. (1991) Literacy and reading performance in the United States from 1880 to present. In Kaestle, C. (ed.) Literacy in the United States: Readers and Readings Since 1880. Yale University Press, New Haven, pp. 75–128.

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20 Replies to “100 Things You Should Know About People: #54 — The Average Reading Level In the USA Is Grade 8”

  1. As usual I think it all depends of who you’re writing for. Some people want that elaborate language because it speeds up their reading — imagine if they had to read expanded abbreviations or side notes each time a scientific word was used.

    Nevertheless, I think it’s safe to write with a few rules of thumb in mind, such as keeping sentences short, avoiding passive voice, etc.

    An interesting story was published two years ago on this very subject: http://www.nytimes.com/2009/08/20/opinion/20cogan.html

  2. I think there might be an error in your post about the reading ease score. Isn’t a higher score better than a lower score (higher means an easier text). So your blog post is better than the “About the governor” pages in that respect :p

  3. HL — good point you made… i shouldn’t be dismayed by the score of 55, but grade level of 15?! That seems a bit high.

    Regis and Leigh — I’ll have to check out the articles you have mentioned. Thanks!

  4. Great information I plan to share with our clients .. so many don’t take education level and the ease of reading their content into consideration.

  5. Susan, thanks for the link to the research. If only readability scores were as helpful as they seem. Ginny Redish has written a couple of excellent articles on the problems with readability scores. See:

    Redish, (2000) ‘Readability formulas have even more limitations than Klare discusses’, ACM Journal of Computer Documentation, Vol 24, No. 3.

    Redish and Selzer, (1985) ‘The place of readability formulas in technical communication’, Technical Communication, Fourth Quarter

    (You’ll find the latter if you search for it on Google, but the link was a nightmare to try to paste in here).

  6. I recommend against using the word “average”. Many internet users are well aware that the word “average” is almost always indicative of manipulation, if not outright lie. Without the data on what kind of “average” is being used (mean, mode, etc.) and how it was derived, no “average” can ever be accepted by a rational person as factual information. I understand you’re probably writing for a less intellectual audience, but then would such an audience really go to an obviously intellectual website like this? Plus there’s something to be said for lifting people up, rather than making it more comfortable for them to stay down.

  7. “For the reading ease score, lower is better. Comic books are at 90, and legal documents are often 10 and under”

    Am I missing something? Comic books are not easy to read, but legal documents are?

    Wow… my brain must be broken!

  8. Chris,

    Thanks for catching that error! I’ve corrected it. A higher reading ease score means it is easier to read.

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