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Readability Score Checker

Get Flesch Reading Ease, Flesch-Kincaid grade and Gunning Fog scores for English text.

What this tool does

Scores how hard a passage is to read using three well-known formulas and reports sentence length, syllables per word and the share of complex words.

Who should use it

Content writers aiming for plain language, teachers, and teams writing help or legal-adjacent copy for general audiences.

How it works

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 × (average sentence length + 100 × complex words ÷ words). Syllables are counted with a vowel-group heuristic.

How to use it

  1. Enter or paste text in the form.
  2. Use "Load example" if you want to see how input should look.
  3. Press the run button. Processing happens instantly in your browser.
  4. Review the result panel, then copy or download the output if the tool offers it. Use Reset to start over.

Practical example

A passage averaging 12 words per sentence and 1.4 syllables per word scores about 77 on Flesch Reading Ease ("Fairly easy").

Understanding the results

Higher Flesch scores mean easier text; grade levels approximate US school years. Aim for the reading level of your audience, not for the lowest score.

Limitations

Formulas only measure sentence and word length. They do not measure clarity, accuracy or tone. Syllable counting is an English-only heuristic, so scores are estimates and other languages are unsupported.

Accuracy and report transparency

Results are computed in your browser from exactly what you enter. Deterministic steps (counting, parsing, encoding, validation) are verified by an automated test-suite with known answers. Where a method is a heuristic, the result panel says "estimated". No external data is used and nothing is invented.

Privacy

Your input never leaves your device for this tool. We count anonymous events (tool opened, run, copied) without storing what you typed. See the Privacy Policy.

Try these next

Sentence Length AnalyzerMeasure each sentence and flag the ones that are too long to scan comfortably.Passive Voice DetectorHighlight sentences that likely use passive voice so you can decide whether to rewrite them.Word CounterCount words, characters, sentences, paragraphs and estimated reading time as you paste text.

Frequently asked questions

Is readability a Google ranking factor?

Google does not list it as one. Readable pages are easier for people to use, which is why we show it as a quality aid.

Is my data sent to your server?

No. This tool runs entirely in your browser, so the text or files you enter stay on your device. We do record anonymous counts of how often each tool is opened or run (no input data) to see which tools are useful.

How accurate are the results?

Counting, parsing, encoding and validation steps are deterministic and covered by automated tests with known answers. Anything based on a heuristic is labelled "estimated" in the result panel.

Is this tool really free?

Yes. There is no account, limit or paid plan. The site is supported by advertising, which is disclosed on our Advertising Disclosure page.

References