Skip to main content ↓

What Is the Coleman Liau Index?

Does your website meet the readability expectations of your target audience? In order to create content that resonates with your audience, you need to understand their readability expectations. In other words, do they expect to read advanced text? Or are you writing to elementary school students? If your website doesn’t meet the readability expectations of your target audience, visitors will likely navigate away from your site. This can detract from potential business, and it also contributes to a higher bounce-rate. On this page, we’ll take a look at the Coleman Liau Index, what it means, and how you can improve your score to attract more qualified traffic to your website.

What is the Coleman Liau Index?

Developed by linguists Meri Coleman and T.L. Liau, the Coleman Liau Index is designed to evaluate the U.S. grade level necessary to understand the text.

Instead of syllables per word and sentence lengths, the Coleman Liau Index relies on characters and uses computerized assessments to understand characters more easily and accurately.

Coleman and Liau developed the formula to automatically calculate writing samples instead of manually coding the text. Unlike syllable-based readability indicators, the Coleman Liau Index does not require users to take into account the syllable-counts in the text. Therefore, passages can easily be scanned into a word processor to calculate the Coleman Liau Index.

According to Coleman and Liau, word length in letters is a better predictor of readability than word length in syllables.

Coleman Liau Index formula: 5.89 x (characters/words) – 0.3 x (sentences/words) – 15.8.

What does my score mean?

The score you receive indicates the U.S. school level a person needs to understand the text. So if you receive a rating of 9.5, your text should be easily understood by a student in 9th or 10th grade.

If you’re writing to elementary school students and your Coleman Liau score indicates the necessity of a high school reading level, you’re probably going to need to re-evaluate your content. On the other hand, you probably shouldn’t score a third-grade level if you’re writing to college students.

In order to effectively communicate with your target audience, your writing needs to reflect the grade level of the people you are trying to reach.

Why is readability important?

Did you know that the average American adult reads at the 7th to 9th grade level?

Understanding the readability expectations of your target audience will help to keep people on your website and engaged with your content.

If your text is too complicated, people will likely navigate away from your site. At the same time, if your site is overly simplistic, this can detract visitors as well.

You also have to understand the audience you’re crafting your message to reach. Are you writing for a medical publication? Your text should probably be more advanced that if you are writing to elementary school students.

In order to meet the readability needs of your target audience, it’s important to understand your Coleman Liau Index score and know how to improve it if necessary.

Want to improve your score?

Interested in finding out more about your Coleman Liau Index and how you can improve your website readability?

Our free readability test tool allows you to calculate your score with the click of a few buttons. And we’ll give you some helpful tips for improving the readability of your text to make sure your website is reaching the right audience.