Readability Checker

Check Flesch Reading Ease, Flesch-Kincaid Grade and Gunning Fog for any text, with a visual gauge and your longest sentences flagged. Free, instant, nothing uploaded.

Readability Checker
Grade level
Avg words / sentence
Avg syllables / word
Gunning Fog
Flesch Reading EaseReads like

Longest sentences to look at

What these numbers are. Flesch Reading Ease and Flesch–Kincaid Grade Level were developed for the US Navy in the 1970s and are now built into word processors and used by many style guides; Gunning Fog estimates the years of formal education a reader needs. All three are formulas based on sentence length and syllable counts — they cannot judge whether your writing is clear, accurate or well argued, and technical terms your audience knows perfectly well will still push the score down. Use them to spot sentences that ran away from you, not as a target to optimise.

User Guide

  1. Enter your URL, keyword or content above.
  2. Run the analysis with one click.
  3. Review your results and actionable insights.

About the Readability Checker

This tool scores how difficult a piece of writing is to read, using the three formulas most widely relied on: Flesch Reading Ease, Flesch–Kincaid Grade Level and Gunning Fog. All three work from the same two signals — how long your sentences are, and how many syllables your words contain — because those two things predict comprehension difficulty surprisingly well.

How to read the score

Flesch Reading Ease runs from 0 to 100, and higher is easier. The gauge shows where your text sits:

ScoreDifficultyTypical reader
90–100Very easy11-year-old
80–90Easy12-year-old
70–80Fairly easy13-year-old
60–70Plain English13–15-year-old
50–60Fairly difficult16–18-year-old
30–50DifficultUniversity student
0–30Very difficultGraduate

Most general-audience writing should land in the 60–70 band. News outlets typically write between 60 and 70, popular non-fiction around 60, and academic papers often below 30. Aiming for a higher score than your subject can bear produces writing that is choppy rather than clear.

What the formulas actually do

Flesch Reading Ease is 206.835 − 1.015 × (words per sentence) − 84.6 × (syllables per word). Flesch–Kincaid converts a similar calculation into a US school grade, so 8.0 means an average eighth-grader could follow it. Gunning Fog estimates years of formal education needed, weighting words of three or more syllables. Both Flesch measures were developed for the US Navy in the 1970s and are now built into word processors and required by plain-language rules in several jurisdictions.

The honest limitation

These are arithmetic, not comprehension. A formula cannot tell whether your argument is coherent, your facts are right, or your paragraph order makes sense. It will penalise correct technical vocabulary your readers know perfectly well — “photosynthesis” and “amortisation” are four and five syllables regardless of how familiar they are to the audience. And it can be gamed: chopping every sentence in half raises the score while making the writing worse. Use it as a smoke alarm for sentences that got away from you, not as a target.

Making writing easier to read

The fastest improvement is almost always sentence length. The tool lists your longest sentences, and splitting anything past about 25 words usually lifts the score more than any word substitution. After that: prefer the shorter word where it means the same thing, cut throat-clearing phrases such as “it is important to note that”, and use active voice, which is both shorter and clearer. Then check the length with the Word Counter and, if you are writing for search, the keyword balance with the Keyword Density Checker.

Frequently Asked Questions

What is a good readability score?

For general audiences, a Flesch Reading Ease of 60–70 — plain English, readable by most adults. Below 30 is graduate-level and hard going; above 80 can feel simplistic for adult readers unless you are writing for children.

How is Flesch Reading Ease calculated?

206.835 minus 1.015 times the average words per sentence, minus 84.6 times the average syllables per word. Long sentences and long words both push the score down.

What does the grade level mean?

Flesch–Kincaid Grade Level maps your text onto US school grades, so 8.0 means an average eighth-grader (about 13–14 years old) should be able to follow it. Most mainstream writing targets grades 7 to 9.

Does readability affect SEO?

Not as a direct ranking factor, but it affects whether people stay and read, which does matter. Clear writing also tends to answer questions more directly, which helps for featured snippets.

How can I improve my readability score quickly?

Split your longest sentences — the tool lists them for you. Anything past 25 words is usually two sentences. After that, cut filler phrases and choose shorter words where they mean the same thing.

Is my text uploaded anywhere?

No. The analysis runs entirely in your browser; nothing you paste is sent to a server.