The Flesch-Kincaid readability tests are popular and long-established ways of measuring how easy your English writing is to read.
They’re useful because the level of difficulty of your text directly influences how well your readers engage with it, and how well they absorb the information or message you want to convey.
There are two related tests: the Flesch Reading Ease Score, and the Flesch-Kincaid Grade Level.
What is the Flesch Reading Ease Score?
The Flesch Reading Ease Score has its origins in education, and the need for texts for learners to be appropriate to their reading level.
The formula for working out the reading score of a text was developed in 1948 by author and writing teacher, Rudolf Flesch (1911-1986).
Flesch was a supporter of plain English - English that is easily understood by the target readers, is clear and concise, with common vocabulary, and is free of language like clichés and jargon.
How does the Flesch Reading Ease Score work?
Using Flesch’s mathematical formula, texts are rated on a 100-point scale.
The higher the score, the easier your text is to read and understand. The lower the score, the more difficult it is to understand.
Readability statistics take into account things like sentences per paragraph, characters per word, and words per sentence.
Texts with high scores will have short sentences and short/common words and will be easier to read.
Those with long sentences and multi-syllable words get lower scores, and are more difficult to read.
The results are interpreted according to the reading age someone needs to be to understand your writing.
A score of 80 to 100 is easily understood by readers aged 10 to 11 A score of 60 to 70 is easily understood by readers aged 13 to 15 A score of 0 to 30 is best understood by university graduates Advice varies but, generally speaking, a score of 60 to 70 is good for most standard written documents.
The Reading Ease Formula
If you’re interested in seeing exactly how it works, this is what the formula looks like (if you’re numerophobic you might want to look away now!):
Reading Ease score = 206.835 − (1.015 × Average Sentence Length) − (84.6 × Average Syllables per Word)
Average sentence length is the number of words divided by number of sentences.
And average syllables per word is the number of syllables divided by number of words.
What is the Flesch-Kincaid Grade Level?
In 1976 the US Navy modified the Flesch Reading Ease formula to produce a grade-level score based on US education grade levels – the Flesch-Kincaid Grade Level - which they used to create easy-to-read training manuals.
Readability scores are interpreted as grades as shown here:
Score 90-100 5th Grade 11 years (British Year 6) Score 90-80 6th Grade 12 years (British Year 7) Score 80-70 7th Grade 13 years (British Year 😎 Score 70-60 8th and 9th Grade 14-15 years (British Years 9 and 10) Score 60-50 10th to 12th Grade 16-18 years (British Years 11 to 13) Score 50-30 College (British University) Score 30-0 College Graduate (British University Graduate) How can we use the Flesch-Kincaid Readability Scores and Grades?
The Flesch-Kincaid tests are useful for anyone who wants to test how easily people can understand a piece of written text.
They’re not infallible, but they can give you an indication of the age and level of education a reader needs to have reached to easily understand your writing.
If you’re a teacher writing educational content you can test your teaching materials, and worksheets etc. to see if the grade level and reading ease scores are appropriate for your students. If not, you can fine-tune them to make them just right. You can also choose the most age-appropriate books to guide your students through reading levels and curriculum work.
Authors and bloggers can use the tests as part of the editing process. The scores can point writers towards ways they can improve their texts. If they have more than two or three sentences per paragraph, or a large number of long sentences, they can edit accordingly.
The tests can be used to improve the readability of newspaper content, and the effectiveness of marketing and advertising materials.
You can use the results to improve your writing to make it either easier to read, or more sophisticated. Whatever suits your audience best.
With judicious use of readability tests, teaching materials can be made more effective, businesses and government departments etc. can ensure the time and money spent on developing written texts is efficient and not wasted, and newspapers can retain and increase readership.
Anyone who produces written texts can make sure their target readers can read their writing, and can understand the information and the message conveyed.
How do I work out the reading ease score and grade level of my text?
You’ll be glad to know you don’t have to use the complicated Flesch-Kincaid formula!
Typely does all the hard work for you. It automatically works out both measures by analysing your text and giving you the relevant score and level, plus a breakdown of things like sentences per paragraph, characters per word, and words per sentence.
Typely will give you suggestions for improvements, and can highlight paragraphs where you can make changes.
And as you make those changes you can see the scores change, so you can keep making improvements until you reach the score and grade you want.
Readability scores have some limitations because they measure the complexity of your writing, and not the quality. The scores also don't take into account other factors such as visual aspects like font size and line and paragraph spacing, which also affect readability and comprehension.
Nevertheless, they are a valuable way of improving your readers’ enjoyment of texts and their levels of engagement with them. They help you ensure your writing is targeting the right age level, and has an appropriate level of complexity according to your audience and context.