Readability Report

The ProWritingAid Team
ProWritingAid: A grammar guru, style editor, and writing mentor in one package.
Published Dec 29, 2015


The Readability report is a favorite of our customers. There's no better way to get an objective evaluation on the clarity of your writing.

This report provides scores from several different established readability tests. Here's what they mean and how to use them.

  1. Flesch-Kincaid Reading Ease Test
  2. Flesch-Kincaid Grade Level Test
  3. Coleman-Liau Index
  4. Automated Readability Index (ARI)
  5. Dale–Chall Readability Formula
  6. How to Use These Scores
  7. Use This Report!

Flesch-Kincaid Reading Ease Test

One of the most trusted readability scores ever created. Based on a 0-100 scale, the Flesch-Kincaid Readability Test yields a higher score for text that's easier to read and a lower score for text that's difficult to read. Here's the formula for the test:

206.835 - 1.015 x (words/sentences) - 84.6 x (syllables/words) (Source)

No need to memorize that—ProWritingAid computes it for you.

Our app recommends that you aim for a 60 or above since most writing for mass audiences scores around this mark. If you find yourself scoring poorly on this test, try shortening your words and sentences. That said, if you're writing exclusively for an educated audience (for example, a university paper), you might aim for a lower score.

Flesch-Kincaid Grade Level Test

This test uses the same principles of the Flesch-Kincaid Reading Ease test and equates it to the American schooling system grade levels. Here's the formula:

0.39 x (words/sentences) + 11.8 x (syllables/words) - 15.59 (Source)

For example, a piece that scores a 2.8 on this test would be considered readable to anyone at a 2nd or 3rd grade reading level. This test is especially helpful to users writing middle-grade, young adult, or children's fiction.

Coleman-Liau Index

The chief difference between this test and the ones we've seen so far is that it's based on characters rather than syllables. This is a bit easier on some machines since syllables are more difficult to define than characters. (ProWritingAid can work with both.) Here's the formula:

5.89 x (characters/words) - 0.3 x (sentences/words) - 15.8 (Source)

Like the Flesch-Kincaid Grade Level Test, the Coleman-Liau Index indicates the American grade level of reading comprehension required to read a text. For example, a score of 5.2 indicates writing that's written at a 5th grade level.

In your reports, you might notice that your Flesch-Kincaid and Coleman-Liau tests differ in their grade levels. For example, the same text might earn a 2 with Flesch-Kincaid and a 5 with Coleman-Liau. Remember, these tests are computing different values (syllables versus characters). In a case like this, the grade level likely falls somewhere in between.

Automated Readability Index (ARI)

Again, this test yields a numerical value corresponding to a grade level. Like the Coleman-Liau Index, the ARI works with characters. The formula:

4.71 x (characters/words) + 0.5 x (words/sentences) - 21.43 (Source)

Since this test is based on character count, it will likely align more closely with your score on the Coleman-Liau Index.

Dale–Chall Readability Formula

This test has a key difference from the others. Rather than determining reading difficulty with syllables or characters, the Dale–Chall method evaluates difficulty based on tests using American fourth graders. Researchers polled a focus group of students and came up with a list of approximately 3,000 words most of them understood. Any words not appearing on that list are considered difficult for the purposes of this test. Here's the formula:

0.1579 - (difficult words/words x 100) + 0.0496 (words/sentences) (Source)

Once again, the final score corresponds to American grade levels.

How to Use These Scores

Okay, formulas are all well and good. But you're probably wondering how these scores can improve your writing.

First, know your objectives. If you're writing a novel, blog post, or how-to guide, you probably want to aim for higher readability scores. This is not to say that you're dumbing down your writing. Rather, these writing mediums are meant to be consumed by a wide audience. Therefore, do your best to ensure they can be read by anyone who's interested in them. Aim for high readability scores with all five of the above tests. Conversely, if you're writing a research paper that's only going to be read by a select audience anyway, you can safely disregard your scores. Your objective here is to write a great paper, which will assuredly require you to use some esoteric language.

Second, know your audience. If you're writing children's picture books, even a Flesch–Kincaid score of 70 might be too high. But if you're writing adult contemporary literary fiction, your audience likely demands a more challenging reading experience.

Third, identify potential weaknesses in your writing. For instance, remember how the Flesch–Kincaid score is based on syllables? If you notice that score is consistently low on your writing, that might indicate you're using too many complex words. Or if you have this problem with your Coleman-Liau Index, you might be being too wordy (Coleman-Liau looks at characters). Use the data to make inferences about your writing habits.

Use This Report!

Keep in mind that your readability scores do not necessarily indicate the quality of your writing. Pick your objectives, know your audience, and identify your weaknesses. Use the Readability report today!

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The ProWritingAid Team
ProWritingAid: A grammar guru, style editor, and writing mentor in one package.

The most successful people in the world have coaches. Whatever your level of writing, ProWritingAid will help you achieve new heights. Exceptional writing depends on much more than just correct grammar. You need an editing tool that also highlights style issues and compares your writing to the best writers in your genre. ProWritingAid helps you find the best way to express your ideas.

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