Flesch · Fog · SMOG · ARI · 6 scores instant

Readability Checker

Paste any text and instantly see six industry-standard readability scores, word/sentence/syllable stats, and highlighted complex words.

Your text
0 words 0 sentences 0 syllables 0 characters ~0 min read
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Complex word Passive voice Long sentence Very long sentence
Estimated Reading Level
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Enter text to analyze
HardEasy
Flesch Reading Ease
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Higher = easier (0–100)
Flesch-Kincaid Grade
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US grade level
Gunning Fog
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Years of education
SMOG Index
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Grade level (3+ sentence)
ARI
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Automated Readability
Coleman-Liau
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Grade level
Top complex words (3+ syllables)
Enter text to see complex words

Which readability formula should you use?

Different formulas weight different factors — syllable count, word length, sentence length. No single formula is definitive; use them together as a guide.

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Flesch Reading Ease

Score 0–100. 60–70 is plain English, 30–50 is college level, under 30 is very complex (legal/technical). Target 60+ for general audiences.

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Gunning Fog

Estimates years of formal education needed. 12 = US high school diploma level. Most newspapers target 8–12. Technical docs often land at 14–18.

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SMOG Index

Specifically designed for health communications. Counts polysyllabic words in 30-sentence samples. Widely used by government and healthcare for patient-facing content.

Frequently Asked Questions

What readability score should I aim for?

For general web content: Flesch 60+, grade level 8–10. For marketing copy: grade 6–8. For medical/legal notices: check SMOG ≤ 8 (6th grade health literacy standard). For academic content, higher grade levels are expected.

How are syllables counted?

Syllable counting uses a phonetics-approximate heuristic: count vowel groups per word, with adjustments for silent-e endings and common patterns. It won't match a dictionary perfectly but is accurate enough for score calculations.

What counts as a "complex word" in Gunning Fog?

Words of three or more syllables, excluding proper nouns, compound words formed from simpler words, and -ing/-ed forms of 2-syllable words.

How many sentences do I need for accurate SMOG?

SMOG is technically designed for 30+ sentence samples. The tool shows a result for shorter texts but flags when the sample is too short for SMOG reliability.