English Reading Level Analyzer
Paste any English text — an article, a chapter, a paragraph — and get its CEFR level (A1 to C2) in seconds. Runs in your browser, no signup.
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CEFR level
B1
Words
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Sentences
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Flesch–Kincaid
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Out of core 1k
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Find more at this level
How the analyzer works
The tool combines two signals:
- Flesch–Kincaid Reading Ease — a classic readability formula based on sentence length and syllables per word. High scores = easy text, low scores = dense text.
- Core vocabulary coverage — the share of words in your text that fall outside the 1 000 most common English words. Higher = more specialised vocabulary required.
The combined score maps to a CEFR band (A1 to C2). It runs entirely in your browser — nothing is sent to a server.
The same algorithm we use here also powers Clue's per-book level tags in the books library.
Frequently asked questions
How does the analyzer work?
Flesch–Kincaid Reading Ease + share of words outside a 1 000-word core list → mapped to CEFR (A1–C2).
Is this an official CEFR scoring?
No — research-based heuristic. Cambridge/IELTS use trained raters. This is a fast estimate, accurate enough to pick reading material.
How much text do I need?
At least 100 words. Two or three paragraphs work best.
Can I link or embed this on my site?
Yes, link to https://tryclue.app/tools/reading-level. No embed widget yet.