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SEO & marketing·Content Seo

Readability Score Checker

Check your text's readability with Flesch Reading Ease, Flesch-Kincaid Grade Level, and Gunning Fog Index. Instant, browser-only, no signup required.

Added May 14, 2026

Quick examples

Input

Result

Enter a value for paste your content to see your result.

How it works

Calculates three industry-standard readability scores — Flesch Reading Ease, Flesch-Kincaid Grade Level, and Gunning Fog Index — to tell you how easy your content is to read and which audience it targets.

Formula

Flesch RE = 206.835 − 1.015·(words/sentences) − 84.6·(syllables/words) | FK Grade = 0.39·(words/sentences) + 11.8·(syllables/words) − 15.59 | Fog = 0.4·(words/sentences + 100·complex_words/words)

words
Total word count
sentences
Total sentence count (split on . ! ?)
syllables
Total syllable count (heuristic-based)
complex_words
Words with 3 or more syllables (excluding common suffixes)

Step by step

  1. 01Count words by splitting the text on whitespace.
  2. 02Count sentences by splitting on sentence-ending punctuation (. ! ?).
  3. 03Estimate syllables per word using a vowel-group heuristic (subtract silent endings, ensure minimum of 1).
  4. 04Compute average sentence length (words ÷ sentences) and average syllables per word.
  5. 05Apply the Flesch Reading Ease formula — higher score = easier to read (target 60–70 for general web content).
  6. 06Apply Flesch-Kincaid Grade Level — output is approximate US grade needed to understand the text.
  7. 07Apply Gunning Fog Index — counts 'complex' words (3+ syllables) to penalise jargon.

Examples

General web article (target audience: adults)

Short sentences and common words produce a high Flesch score (typically 70+) and a low grade level, making it suitable for most readers.

Inputs

Paste your content:
The quick brown fox jumps over the lazy dog. A fast red car drove past the old stone bridge. Children played happily in the warm summer sun. The teacher explained the lesson clearly to every student in the class.

Result

Reading level:
Easy — 6th–7th grade
Note: Syllable counting uses a heuristic — results may differ slightly from paid tools that use lookup tables. Aim for Flesch RE ≥ 60 (grade ≤ 8) for blog posts and landing pages targeting a general audience. Academic and technical writing typically scores 30–50 on Flesch RE — that may be appropriate for the context. Shorter sentences and fewer multi-syllable words are the fastest way to improve readability.

Related guides

  • What Is Flesch Reading Ease Explained?

    Explains Flesch Reading Ease, Flesch-Kincaid Grade Level, and Gunning Fog Index — how each formula works, what scores mean, and which targets to aim for by.

  • How to Improve Content Readability

    Actionable techniques to raise readability scores and communicate more clearly: shorter sentences, simpler words, active voice, better structure, and a.

Frequently asked questions

What is a good Flesch Reading Ease score?

Flesch Reading Ease ranges from 0 (very difficult) to 100 (very easy). For most web content, aim for 60–70 — this equates to an 8th–9th grade reading level and is comfortable for most adults. Scores of 70–80 suit consumer-facing content; 30–50 is typical for academic or technical writing.

What is the Flesch-Kincaid Grade Level?

The FK Grade Level estimates the US school grade required to understand the text. A score of 8 means an 8th-grader could follow it. For general marketing or blog content, target grade 6–9. Legal or scientific texts commonly reach grade 12–16.

What is the Gunning Fog Index?

Gunning Fog penalises long sentences and 'complex' words (3+ syllables). A score under 12 is considered accessible; scores of 17+ approach academic difficulty. Reducing sentence length and replacing jargon with plain language brings the score down.

Why do different readability tools give slightly different scores?

Syllable counting is the main source of variation — most tools use heuristic algorithms rather than dictionary lookups, and each heuristic handles edge cases (silent e, compound words, proper nouns) differently. Treat the scores as directional guides rather than exact measurements.

Does readability affect SEO directly?

Google does not use a readability score as a direct ranking signal, but readability influences dwell time, bounce rate, and social sharing — all of which correlate with rankings. Content that matches your audience's reading level tends to earn more engagement and backlinks.