What Is a Good Readability Score?

Readability tools give you a number, but the number only helps if you know what it measures and what counts as "good" for your readers. The short answer: there is no single good score. A help page for the general public and a technical paper for specialists should land in different places. This guide explains what readability scores measure, how to read the two most common ones, and how to use them to make writing clearer rather than just chasing a target.

Formula details in this guide come from the original sources linked below. Advice on what to aim for is WriterFlowLab's editorial guidance, not a standard. You can check any text with our free readability score checker.

What readability scores measure

Most readability formulas look at just two things:

• Sentence length: the average number of words per sentence.
• Word length: the average number of syllables per word, or in some formulas the average number of letters per word.

Longer sentences and longer words push a text towards "harder". That is all the formulas see. They do not read your text the way a person does, so they cannot tell whether it is accurate, well organised, friendly, or easy to act on. A short sentence full of unfamiliar jargon can score as easy, and a careful explanation with a few necessary technical terms can score as hard.

That makes a readability score a useful warning light, not a verdict. It is good at spotting long sentences and heavy vocabulary. It cannot tell you whether your reader will understand you.

Flesch Reading Ease

The Flesch Reading Ease score was published by Rudolf Flesch in 1948 in the paper "A new readability yardstick". It is calculated as:

206.835 − (1.015 × average sentence length) − (84.6 × average syllables per word)

Scores usually fall between 0 and 100, and higher means easier. Very simple text can score above 100 and very dense text can score below 0, because the formula has no built-in floor or ceiling. A commonly used interpretation of the scale is:

• 90 and above: very easy
• 80 to 89: easy
• 70 to 79: fairly easy
• 60 to 69: standard
• 50 to 59: fairly difficult
• 30 to 49: difficult
• Below 30: very difficult

Our guide to Flesch Reading Ease works through the formula with examples.

Flesch-Kincaid Grade Level

The Flesch-Kincaid Grade Level uses the same two inputs but expresses the result as a US school grade. It comes from a 1975 report by J. Peter Kincaid and colleagues, who recalculated readability formulas for US Navy enlisted personnel reading Navy training material:

(0.39 × average sentence length) + (11.8 × average syllables per word) − 15.59

Here higher means harder. Microsoft's Word documentation describes it this way: a score of 8.0 means an eighth grader can understand the document.

Other grade-level formulas

Several other formulas also estimate a US grade level, each with a slightly different recipe:

• Gunning Fog Index: sentence length plus the share of "complex" words with three or more syllables.
• SMOG Index: based on the number of words with three or more syllables. It was designed for samples of 30 sentences, so it is a rough estimate on shorter text.
• Automated Readability Index (ARI) and Coleman-Liau Index: count letters per word instead of syllables.

Because each formula weighs things differently, it is normal for them to disagree by a grade or more on the same text. Look at the overall picture rather than one number.

So what is a good readability score?

It depends on who is reading. As a reference point, Microsoft's Word documentation suggests a Flesch Reading Ease score between 60 and 70 for most standard documents, and a Flesch-Kincaid grade of around 7.0 to 8.0 for most documents.

As a practical starting point (our editorial guidance, not a rule):

• General web content, help pages and instructions: for content aimed at the general public, many writers aim for a relatively accessible level. Somewhere around 60 or above on Flesch Reading Ease is a reasonable place to start checking, but meaning and task completion matter more than the number.
• Professional and business writing: a somewhat lower Reading Ease is normal when readers share specialist vocabulary. Long sentences are still worth breaking up.
• Academic and technical writing: lower scores are expected because necessary terms are long. Focus on clear structure, defined terms and one idea per sentence instead of the score.
• Content for children or language learners: aim much easier, and test with real readers if you can.

Why there is no universal "perfect" score

• Formulas ignore meaning. They cannot tell a clear sentence from a confusing one of the same length.
• Familiar long words count as hard. "Information" and "community" push scores down even though most readers know them well.
• Chopping sentences can game the score. Splitting every sentence in two raises the score but can make text choppy and hide how ideas connect.
• Context changes the target. A legal notice, a product page and a research summary have different readers and jobs.
• The formulas were built for English. Syllable-based scores are not meaningful for other languages, and syllable counts are estimates even in English, so different tools often give slightly different scores for the same text.

Practical ways to improve readability

1. Split long sentences. Plain-language guidance from digital.gov advises expressing only one idea in each sentence. Our guide on how long a sentence should be covers this in more detail.
2. Prefer familiar words. Use "use" rather than "utilize" and "help" rather than "facilitate" when the meaning is the same. Keep technical terms your readers expect, and define them on first use.
3. Cut filler. Phrases such as "in order to" and "it is important to note that" add length without meaning.
4. Keep paragraphs focused. One topic per paragraph, and break up long blocks. See how many sentences a paragraph should have.
5. Use headings and lists so readers can scan, especially on phones.
6. Clean pasted text first. Stray line breaks and spaces from copying can affect how tools split sentences and paragraphs. The text cleaner fixes these before you check.
7. Read it aloud. If you run out of breath or stumble, the sentence probably needs work.

How to check your readability score

1. Paste your text into the readability score checker. Use at least 100 words if you can, because very short samples give unstable scores.
2. Look at the Flesch Reading Ease score and the grade-level scores together.
3. Read the "What to improve" suggestions and the highlighted long sentences.
4. Edit, then check again. Use the word counter to confirm that your edit tightened the text rather than padding it.

The checker runs in your browser, so your text is not uploaded or stored.

Sources

• Flesch, R. (1948). A new readability yardstick. Journal of Applied Psychology, 32(3), 221–233.
• Kincaid, J. P., Fishburne, R. P., Rogers, R. L., and Chissom, B. S. (1975). Derivation of new readability formulas for Navy enlisted personnel. Research Branch Report 8-75.
• Microsoft Support: Get your document's readability and level statistics.
• Digital.gov plain language guide: Clear and short.