Readability Score Checker
100% private — runs on your device, never uploaded. Works offline once loaded.
Paste any text to get instant Flesch Reading Ease, Flesch-Kincaid Grade and Gunning Fog readability scores, plus word, sentence and syllable counts. All analysis runs privately in your browser.
Why readability matters
Readability measures how easily a reader can understand your writing. It matters for SEO because clear content keeps visitors on the page, reduces bounce, and helps search engines and AI systems parse your meaning. It matters even more for accessibility: government and healthcare guidelines often recommend writing at a grade 7–8 level so the widest possible audience can follow along.
This tool applies three of the most established readability formulas to any text you paste and reports the underlying counts — words, sentences, syllables and complex words — so you can see exactly what is driving the scores.
The formulas, exactly
All three formulas are computed from the same building blocks: total words, total sentences, total syllables, and the number of 'complex' words (three or more syllables). The math is transparent so you can reproduce it:
- Flesch Reading Ease = 206.835 − 1.015 × (words / sentences) − 84.6 × (syllables / words). Higher is easier; 100 is very simple, 0 is very dense.
- Flesch-Kincaid Grade = 0.39 × (words / sentences) + 11.8 × (syllables / words) − 15.59. The result is a U.S. school grade level.
- Gunning Fog = 0.4 × ((words / sentences) + 100 × (complex words / words)). Also a grade level, but driven by long sentences and multi-syllable words.
How to improve your score
The two biggest levers are sentence length and word complexity, because both appear in every formula. Break long, comma-spliced sentences into shorter ones. Replace multi-syllable words with plain alternatives ('use' instead of 'utilize', 'help' instead of 'facilitate'). Prefer active voice, cut filler, and use lists where they fit.
Recompute as you edit — the scores update live — and target a Flesch Reading Ease around 60–70 and a grade level of 7–9 for general web content. Save denser writing for audiences who expect it, like academic or legal readers.
Caveats to keep in mind
Readability formulas are proxies. They count structure — sentence and word length — not meaning, logic or accuracy. A text can score as 'easy' while being poorly organized, and technical jargon that a specialist audience knows well will still inflate the grade level. Very short samples produce noisy scores, so paste a full paragraph or article for a reliable reading.
The syllable count uses a heuristic rather than a dictionary, so a handful of irregular words may be off by one syllable. Across a normal-length text these small errors average out and barely move the scores.
Frequently asked questions
Is my text uploaded to a server?
No. The entire analysis — counting words, sentences and syllables and computing all three scores — runs in your browser with JavaScript. Your text never leaves your device.
How are sentences detected?
The tool splits the text on sentence-ending punctuation (period, exclamation mark, question mark) and counts the non-empty segments. Abbreviations and decimals can occasionally cause a small miscount, so very unusual formatting may shift the sentence total slightly.
What counts as a 'complex word' in Gunning Fog?
A complex word is one with three or more syllables. Gunning Fog uses the percentage of complex words, along with average sentence length, to estimate the reading grade level.
Which score should I focus on?
For general web writing, use Flesch Reading Ease as your headline metric (aim for 60+) and treat the grade-level scores as a cross-check. If your audience is students or a specific reading level, the Flesch-Kincaid Grade is the most direct target.
Why do my three scores disagree?
Each formula weights sentence length and word difficulty differently, and Gunning Fog uses complex-word count rather than raw syllables. They rarely match exactly, but they should point in the same direction — all easier or all harder.
Does readability affect Google rankings?
Not as a direct ranking factor. But clearer content improves engagement, dwell time and comprehension, which support your overall SEO and make your page more useful to readers and AI summarizers alike.
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