π CEFR Level Estimator
Paste English text and get an estimated CEFR level from A1 to C2, with the metrics behind it.
Text Complexity Estimate
Approximate heuristic, not an official language test. It measures text complexity, not your personal English level.
How to Use This Estimator
Paste English prose into the box and click Analyze Text. The tool measures five complexity signals, converts them into a Flesch-Kincaid grade level, and maps that to a CEFR band from A1 (beginner) to C2 (proficient). Always read the metrics table and the reasoning bullets: they show you exactly why the text got its band.
Paste at least 50 words of connected English prose. For the most reliable result, paste 150 to 400 words, such as several paragraphs.
Click Analyze Text. Short texts, bullet lists, and dialogue will skew the result, so use normal paragraphs.
Read the estimated band, then scan the metrics table: average sentence length, average word length, share of long words, lexical diversity, and Flesch-Kincaid grade.
Read the reasoning bullets to see which signals pushed the band up or down, and use that feedback to adjust your own writing.
How the Estimate Is Calculated
The core idea is simple: harder texts use longer sentences and longer words. The Flesch-Kincaid grade level turns that into a US school grade, which maps roughly onto the CEFR bands as shown below. Two adjustments refine the result: texts with very long sentences (25 or more words on average) and a high share of long words (20 percent or more) move up one band, while texts with very short sentences (6 words or fewer) and few long words (10 percent or less) move down one band. Syllables are counted with a standard vowel-group heuristic, which is approximate but consistent.
Worked Example: Three Passages, Three Bands
We ran three real passages through the estimator to check the calibration. Passage 1 is a simple children's story of 78 words: average sentence length 3.9 words, average word length 3.1 characters, only 1.3 percent long words, Flesch-Kincaid grade 0.0. Result: A1. Passage 2 is a general-interest paragraph about remote work, 88 words: average sentence length 14.7 words, 20.5 percent long words, Flesch-Kincaid grade 7.4. Result: B2. Passage 3 is a dense academic paragraph on macroeconomic policy, 68 words: average sentence length 17.0 words, 72.1 percent long words, Flesch-Kincaid grade 25.1. Result: C2. The metric values move in the same direction as a human judge would, which is exactly what a heuristic needs to do.
Using the Result to Improve Your Writing
If your text lands below your target band, the fix is rarely to sprinkle in longer words. Examiners and readers reward clear structure first. Combine short sentences with linking words such as however, although, and consequently to build longer, connected sentences. Replace repeated everyday words with precise alternatives, but keep them natural: say that is misleading instead of that is wrong, not that is fallacious unless the context fits. Watch the metrics table: if your average sentence is under 8 words, you are writing at A2 to B1 sentence patterns no matter what vocabulary you use. Finally, remember the limits: this tool reads complexity, not correctness. A paragraph full of long words with broken grammar will still score high, so keep a human teacher or editor in the loop for real feedback.
Frequently Asked Questions
What is the CEFR?
The CEFR (Common European Framework of Reference for Languages) is the standard scale for describing language ability. It has six levels: A1 (Beginner), A2 (Elementary), B1 (Intermediate), B2 (Upper Intermediate), C1 (Advanced), and C2 (Proficient). Schools, universities, and employers worldwide use these levels to describe what a learner can do with a language.
How accurate is this estimator?
It is an approximate heuristic, not a test of your personal English level. It measures the complexity of the TEXT you paste, using sentence length, word length, syllable density, and vocabulary variety. It cannot judge grammar accuracy, idioms, or how well the text is written. For an official level, take a real exam such as IELTS, TOEFL, or a Cambridge English test.
How much text do I need to paste?
At least 50 words. Complexity metrics are noisy on short samples: a single long sentence can skew everything. For a reliable estimate, paste 150 to 400 words of connected prose, such as a few paragraphs of an article, essay, or story.
Which metrics matter most for the estimate?
Average sentence length and the Flesch-Kincaid grade level carry the most weight, because long, clause-heavy sentences are the strongest signal of advanced text. Word length and the share of long words come next, since advanced texts use more abstract Latin-based vocabulary. Lexical diversity (type-token ratio) is the weakest signal, because even simple texts can repeat few words or use many.
Can I use this to test my own writing?
Yes, that is one of its best uses. Paste your own essay or email and see which band it lands in, then compare it with the band you are aiming for. If you want to write at B2, for example, you will usually need longer sentences, more varied linking words, and less repetition. Do not game the metric by pasting in long words: examiners reward clear, correct writing, not inflated vocabulary.