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.