New Dale-Chall Readability Formula

The Dale-Chall Readability Formula is useful in figuring out readability. It has been used in schools to determine the right type of text to be used, particularly for kids at 4th and 5th-grade levels. The Dale-Chall Readability Formula can measure vocabulary knowledge, language skills, and comprehension knowledge. A top feature of the Dale-Chall Readability Formula is that it helps highlight all the unnecessary words in a text that make it more difficult for kids to read.

Let’s figure out just what the D-C Readability Index is

The D-C (Dale-Chall) Readability Index is a formula similar to other reading formulas that you might have heard about. This one is used to calculate the grade level of any piece of text that the 4th and 5th graders are reading. It helps to determine whether they can read and understand it.

Incredible people were responsible for creating the D-C readability index

Two professors were Robert Chall and Robert Dale [1]. Even though they created it long ago, it is still commonly used for measures of readability for web pages. This makes the web pages available to the readability levels of people.

Edgar Dale was a professor of education. He was well-known for his knowledge of communications at the Ohio State University. He was determined to improve the readability of reading materials such as pamphlets, books, and newsletters by creating an accurate readability formula.

Edgar Dale, along with Jeanne Chall, developed the Dale-Chall Readability Formula in 1948. It was considered highly reliable for providing accurate readability scores for many decades.

In 1983, Jeanne was also responsible for adding Stages of Reading Development to her outstanding contributions to readability and literacy. She went on to develop the Qualitative Assessment of Text Difficulty: A Practical Guide for Teachers and Writers along with three of her graduates. She was also the founder-director of the Harvard Reading Laboratory and made huge contributions towards readability!

It was Rudolph Flesch with his Flesch Reading Ease Formula who inspired both Edgar Dale and Jeanne Chall to revolutionize the way that people see documents. 

The Dale-Chall Formula, unlike other formulas, uses a count of ‘hard’ words

Not only does the Dale-Chall Formula calculate the US grade level of a text sample based on sentence length, but also the number of ‘hard’ words. What are ‘hard’ words? These are words that don’t appear on a special list of common words that most 4th-grade students would be familiar with.

There were 763 familiar words on the original Dale-Chall Formula. But the new Dale-Chall Formula, which came out in 1995, expands this list of familiar words to 3000. Even though the New Dale-Chall Score is particularly aimed at 4th-grade readers, it can be used by older people too across different industries.

Other opportunities the D-C Readability Index provides

The D-C Readability Index has proven useful for evaluating how difficult text is to read and understand. That means the number of syllables is taken into account, and the index will also assess whether your text is too long or too short and how easy it is to comprehend.

Reading text can be difficult for people who aren’t used to it. When you use the D-C Readability Index, you can tell the difficulty level of what you are reading. This will help you when you write articles for websites for a large audience. You will find out if your article is actually readable for the reading skills of your target audience.

Want to know how you measure Dale-Chall Readability Scores?

It is very simple to use the Dale-Chall Readability Calculator. Just remember this; the greater the difficulty of the text, your score will be higher.

To calculate the readability level of text, there are a set of rules which is based on the reading levels determined by 4th and 5th readers; in other words, there is a formula to follow.

The New Dale-Chall Readability Formula will look something like this:

Raw Score = 0.1579 * (PDW) + 0.0496 * ASL

o The raw score equals the reading grade of readers who are able to comprehend text at 3rd grade or below.

o The PDW = the Percentage of Difficult Words

o ASL = the Average Sentence Length in words

If the PDW is greater than 5%, then:

The adjusted score equals the raw score + 3.6365, otherwise, the adjusted score equals the raw score.

The adjusted score equals the reading grade of someone who reads and comprehends text at a 4th-grade level or higher.

Use the free Dale-Chall Readability Calculator to get the grade level of your text

The Dale-Chall Formula compares its word list with the text you have written. It will then calculate a U.S. grade level. The formula is aimed at students above the 4th-grade level. If you want a readability tool to calculate text below the 4th-grade level, use the free Spache Readability Tool.

The D-C Readability Formula is one of the most widely used readability formulas

The best way to improve your score is easy – just write simple English. No complex sentences or big words should be used. Use words that you would choose in everyday conversations and you’ll be fine. In these modern times, newer, more clear-cut formulas are in existence such as Readable.

Look at the revised Dale-Chall readability scores and what they mean:


The New Dale-Chall Formula ensures that text is suitable for 4th graders, but the formula does not only apply to children. It is also used for people with additional learning needs. Remember that readability and accessibility go hand-in-hand.

When you use the New Dale-Chall Readability Index, you will find that you reach a wide audience with greater success.

All Readability Tests:

Here is a list of all readability tests.

Jonathan Gillham

Founder / CEO of I have been involved in the SEO and Content Marketing world for over a decade. My career started with a portfolio of content sites, recently I sold 2 content marketing agencies and I am the Co-Founder of, the leading place to buy and sell content websites. Through these experiences I understand what web publishers need when it comes to verifying content is original. I am not For or Against AI content, I think it has a place in everyones content strategy. However, I believe you as the publisher should be the one making the decision on when to use AI content. Our Originality checking tool has been built with serious web publishers in mind!

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