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Words
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Sentences
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Complex words
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Reading time
Sentence-length distribution
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Consensus grade
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Sentences to fix
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Annotated text
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Six readability formulas
What is readability scoring?
Readability scoring estimates how hard a passage of text is to read by combining two simple ideas: longer sentences are harder to follow, and longer words are harder to decode. The output is a US school grade — a score of 8 means a typical 8th grader can read your text comfortably. Lower means easier; higher means harder.
No single formula is definitive. This calculator shows six standard formulas at once — Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and the Automated Readability Index — and averages them into a consensus grade. Outliers between formulas tell you what kind of edit will move your score the most: a Gunning Fog spike means jargon; a SMOG spike means complex-word density; a Flesch-Kincaid jump alone means sentence length.
Which readability formula should I use?
| Formula | Best for |
|---|---|
| Flesch-Kincaid Grade Level | General web content, government plain-language work, the de-facto default |
| Flesch Reading Ease | Yoast SEO scoring, marketing copy — uses a 0–100 scale where higher means easier |
| Gunning Fog Index | Business and policy writing, jargon-heavy text |
| SMOG Index | Healthcare and patient-information (AMA standard) |
| Coleman-Liau Index | Technical writing, automated scoring (character-based, no syllable counting) |
| Automated Readability Index | Machine-friendly scoring, character-based; what most automated pipelines use |
What's a good readability score?
It depends on the audience. Common Flesch-Kincaid grade-level targets by content type:
| Audience | Grade target |
|---|---|
| Children K–6 | Grade 6 or below |
| Patient-facing healthcare (AMA) | Grade 6–8 |
| General public / blog content | Grade 7–9 |
| Marketing email + landing pages | Grade 6–7 |
| Government plain language (Plain Writing Act) | Grade 8 or below |
| Legal / compliance disclosures | Grade 11 or below |
| Technical / professional | Grade 13–14 |
| Academic / research | Grade 16+ |
For deeper guidance, see what counts as a good readability score and how to improve your score.
How this calculator works
- Paste your text into the composer above. The text never leaves your browser — all scoring runs client-side.
- Read the scores across all six formulas, plus the consensus grade. Each formula card shows whether the score is in target for your chosen audience preset.
- Edit the worst offenders. Sentences flagged red are over 25 words; amber are 16–25. Click any flagged sentence for specific fix suggestions and rewrite hints.
The full scoring engine — syllable counting, sentence splitting, formula math — runs in your browser. We don't store, transmit, or log the text you paste. Useful for unpublished drafts, internal policy text, patient-facing material, or any content you don't want to upload to a third-party service.
Frequently asked questions about readability
Is Readability Check really free?
Yes. No paid tier, no signup, no API key, no usage limit. The calculator and all six formula reference pages are free forever. The site is supported by display advertising on the reference pages; the calculator itself is ad-free.
Does my text leave my browser?
No. The full readability engine runs client-side. Nothing is sent to any server. Useful for unpublished drafts, internal policy text, patient-facing material, or any content you don't want to upload to a third-party service.
Which readability formula is most accurate?
None individually. Each was calibrated for a different context — SMOG for healthcare, Gunning Fog for business writing, Coleman-Liau for technical text. The consensus across all six is more defensible than any single number.
What's a good Flesch-Kincaid grade for blog posts?
Grade 7–9 for general-audience writing. Most popular blogs target grade 8. Marketing copy often goes lower (grade 6–7) for conversion. Technical content typically lands at grade 12 or higher.
How do I lower my readability grade?
Two highest-leverage edits: shorten sentences over 25 words, and swap multi-syllable words for shorter alternatives. "Utilize" becomes "use"; "implementation" becomes "rollout." See how to improve your score for eight tactical edits.
Can I embed this calculator on my own site?
Yes. See the embed page for a one-tag iframe snippet. Free forever, light and dark themes, no API key, no rate limit.
Does this calculator work offline?
Once the page is loaded, yes — all six formulas compute entirely in your browser with no network calls. You can disconnect from the internet after the page loads and keep scoring.
What's the difference between this and Hemingway Editor?
Hemingway is a style coach — it flags passive voice, adverbs, and complex phrases. Readability Check is a grade-level calculator — it shows you six formulas plus a consensus grade. See vs. Hemingway for the full comparison.