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Free Readability Score Checker

A free readability score checker analyzes any text and calculates Flesch Reading Ease, Flesch–Kincaid Grade Level, and Gunning Fog Index from sentence, word, and syllable counts. Paste your writing and get plain-English interpretations (for example, “Easy to read — suitable for 6th grade level”) — no signup, runs entirely in your browser.

Paste any block of text and instantly see three classic readability scores: Flesch Reading Ease, Flesch–Kincaid Grade Level, and Gunning Fog Index. Results include a clear interpretation so bloggers, students, and content writers know whether the writing is easy, standard, or difficult. All math uses standard formulas from word, sentence, and syllable counts — pure client-side JavaScript with no libraries or uploads.

Paste a few sentences to see Flesch Reading Ease, Flesch–Kincaid Grade Level, and Gunning Fog Index with plain-English interpretations.

Runs 100% in your browser. Your data never leaves your device.

Pure JavaScript math from standard formulas: Flesch Reading Ease = 206.835 − 1.015×(words÷sentences) − 84.6×(syllables÷words); Flesch–Kincaid Grade = 0.39×(words÷sentences) + 11.8×(syllables÷words) − 15.59; Gunning Fog = 0.4×((words÷sentences) + 100×(complex words÷words)). Syllables are estimated with vowel-group heuristics; complex words are those with three or more syllables. Everything runs locally with no external libraries.

How to Use Readability Score Checker

  1. Paste or type your text in the input box
  2. Scores update instantly as you type or paste
  3. Read the overall interpretation and each score’s plain-English meaning
  4. Use word, sentence, syllable, and complex-word counts to see what drives the scores

When Would You Use This?

Bloggers and newsletter writers paste drafts to see if posts sit in the “easy” or “plain English” Flesch band before publishing for a general audience.

Students trimming essay complexity check Flesch–Kincaid and Gunning Fog so the grade level matches the assignment without installing desktop software.

Content marketers rewriting product pages compare before-and-after scores after shortening sentences or swapping long words — then jump to the Word Counter for length limits.

Frequently Asked Questions

Is this readability checker free to use?
Yes, completely free. No signup, no login, no payment ever.
Do I need to create an account?
No account needed. Open the tool, paste your text, and see scores immediately.
Is my data safe?
Everything runs in your browser. Your text is never uploaded to our servers.
What scores does this tool calculate?
Flesch Reading Ease (0–100 style score — higher is easier), Flesch–Kincaid Grade Level (U.S. school grade estimate), and Gunning Fog Index (years of education typically needed to understand the text on first reading).
What does “Easy to read — suitable for 6th grade level” mean?
That interpretation comes from the Flesch Reading Ease band (roughly 80–89). It means average 6th-grade readers should find the text comfortable — not that only 6th graders can read it.
How are syllables and complex words counted?
Syllables are estimated with English vowel-group heuristics (including silent-e handling). For Gunning Fog, any word with three or more syllables counts as a complex word.
Does this work offline?
Yes. Once the page has loaded, all readability math works fully offline.

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