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Readability checker

Free readability checker: paste any content and get an instant Flesch score, Gunning Fog index, passive voice %, sentence histogram, and specific suggestions to make your writing clearer.

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Paste your content on the left and readability scores will appear here instantly: no button needed.

Flesch Score
Ease of reading (0–100)
Gunning Fog
Grade level needed to understand
Passive Voice
% of sentences using passive voice
Sentence Histogram
Distribution of sentence lengths

Flesch Score Reference

90–100
Very Easy
Age 11 / 5th grade
80–90
Easy
Age 12 / 6th grade
70–80
Fairly Easy
Age 13 / 7th grade
60–70
Standard
8th–9th grade
50–60
Fairly Difficult
10th–12th grade
30–50
Difficult
College level
0–30
Very Difficult
Professional / Academic
7
readability metrics
Flesch score, Flesch-Kincaid grade, Gunning Fog, passive voice %, reading time, sentence length distribution, and complex word percentage — all from one paste.
Live
updates as you type
Every metric recalculates with each keystroke. No submit button: paste your content and results appear instantly in the panel on the right.
Free
browser-only analysis
Your text never leaves your device. All readability analysis runs locally in JavaScript — safe for confidential documents and unpublished drafts.

What does this readability checker measure?

Seven metrics covering reading ease, grade level, sentence complexity, and passive voice — all from one text input.

Flesch Score

  • 0–100 scale (higher = easier)
  • Computed from avg sentence length
  • And avg syllables per word
  • Rudolf Flesch formula (1948)

Grade Level

  • Flesch-Kincaid grade level
  • Gunning Fog index
  • Both US grade equivalents
  • College, high school, or middle school

Complexity

  • Complex word % (3+ syllables)
  • Average sentence length
  • Long sentences (30+ words) count
  • Sentence length histogram

Voice & Time

  • Passive voice % by sentence
  • Reading time (238 WPM)
  • Sentence difficulty colour view
  • Specific improvement suggestions

Who uses this readability checker?

BL

Bloggers & content writers

Confirm posts hit a 60–70 Flesch score before publishing. Use the sentence difficulty view to identify and shorten the red-highlighted overlong sentences.

SE

SEO teams

Verify long-form content stays within the appropriate Flesch range for the target audience. High bounce rates from confusing content are a negative engagement signal.

ST

Students & academics

Calibrate academic writing to the right complexity level. Grade level output shows whether your essay reads at the expected difficulty for your course.

ED

Editors & teachers

Spot passive voice clusters and overlong sentence patterns in client or student documents. Use the histogram to see exactly where sentence length skews high.

How to check readability: step by step

01

Paste your content

Paste your blog post, article, email, or any text into the input on the left. The readability checker requires at least 50 characters to compute meaningful scores.

02

Read your Flesch score

Your Flesch Reading Ease score appears immediately. 60–70 is standard for general web content. Below 50 means most readers will struggle. Above 80 is very easy.

03

Check the sentence view

Scroll down to the Sentence Difficulty View. Orange-highlighted sentences are hard (21–30 words); red means very hard (30+ words). Shorten these first.

04

Apply the suggestions

The Suggestions panel shows specific fixes: shorten sentences over a specific length, reduce complex words, reduce passive voice. Apply each fix and re-check.

Readability checker: Flesch score, grade level, and reading time

Content that is hard to read gets abandoned. Studies consistently show that readers leave pages with a Flesch Reading Ease score below 40 at significantly higher rates. The Flesch score — developed by linguist Rudolf Flesch in 1948 and still the industry standard — measures readability on a 0–100 scale based on average sentence length and average syllables per word. A score of 60–70 targets a standard US 8th–9th grade reading level, which is appropriate for most general-audience websites. Run this readability checker on every draft to confirm your score before you publish.

This readability checker also computes Flesch-Kincaid Grade Level, Gunning Fog index, estimated reading time, average sentence length, and complex word percentage. Readability affects E-E-A-T signals indirectly: Google's quality rater guidelines assess whether content is appropriate for its intended audience. High bounce rates caused by confusing content are a negative engagement signal. Pair this readability checker with the clarity checker to catch passive voice and filler phrases, and the grammar checker for error-free copy.

SEO teams use this readability checker to confirm that long-form content stays within the 60–70 Flesch range before publishing. Content writers use it to shorten sentences that push grade level above their target audience. After checking readability, verify keyword balance with the keyword density tool and remove AI writing patterns with the passive voice remover.

Frequently asked questions

60–70 is considered standard for most general web content. 70–80 is easily understood by most readers aged 11+. Scores below 30 are typical of academic journals and professional legal text. Blog posts and marketing copy perform best above 50.
Indirectly. Google's quality rater guidelines assess whether content is appropriate for its intended audience. Content that is consistently too hard or too easy for its target readership signals lower quality. High bounce rates from confusing content also feed into engagement signals.
It estimates the US school grade a reader needs to understand the text. A grade level of 8 means an 8th grader can follow the content. It's calculated from average sentence length and average syllables per word — the same inputs as the Flesch score, weighted differently.
Gunning Fog estimates the years of formal education a reader needs to understand the text on first reading. A Fog score below 12 is considered ideal for most audiences. Above 17 is typical of academic or technical writing.
Completely free. This readability checker runs in your browser — no text is sent to a server. No signup or account required. Paste your content and results appear instantly.
The checker scans each sentence for a be-verb (am, is, are, was, were, be, been, being) followed by a past participle. Stative adjectives that look like passive constructions (interested, tired, excited) are excluded. Passive voice % is the number of passive sentences divided by total sentences.

Pairs well with

Check readability, then verify clarity, grammar, and keyword density before publishing.

Make your writing readable.

Free, instant, no signup. Paste your content and get Flesch score, grade level, passive voice %, and clear fixes.