Lexile reading level
A score from 200L to 1600L that tells you how complex a text is to read. Used by most U.S. school districts to match students with texts at the right level. Combines word frequency and sentence length.
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What it measures
What CoGrader's vocabulary analyzer measures
CoGrader's free vocabulary analysis measures three frameworks K-12 teachers use: Lexile reading level, Academic Word List coverage, and Tier 2 academic vocabulary.
Academic Word List coverage
The percentage of words in the text that belong to the Academic Word List, a signal of how academic the writing reads. Casual writing scores under 4%. Strong K-12 academic writing typically lands between 6% and 12%.
Tier 2 vocabulary
The high-utility academic words that show up across subjects but rarely in casual speech. The words most worth teaching directly, and worth practicing for stronger essays. The analyzer pulls them out as a ready-to-teach list.
Methodology
Built on published research
The free vocabulary analyzer is based on three official vocabulary frameworks.
Lexile (MetaMetrics)
Lexile measures combine word frequency (how common a word is in published English) and sentence length (a proxy for syntactic complexity). The framework is maintained by MetaMetrics and used by most U.S. school districts and state assessments. Our value is an estimate suitable for instructional decisions, not an official Lexile certification.
Academic Word List (Coxhead, 2000)
The Academic Word List is 570 word families compiled by Averil Coxhead from a 3.5-million-word corpus of academic texts across the arts, commerce, law, and science. AWL words make up roughly 10% of words in academic writing and about 1% of words in fiction. The full list is published by the School of Linguistics and Applied Language Studies, Victoria University of Wellington.
Tier 2 vocabulary (Beck, McKeown, and Kucan, 2002)
The three-tier framework comes from Bringing Words to Life: Robust Vocabulary Instruction. Tier 1 is everyday speech ("table", "happy"). Tier 3 is domain-specific ("photosynthesis"). Tier 2 sits in between: high-utility academic words that cross subjects. The framework is the basis for direct vocabulary instruction in most U.S. K-12 ELA curricula.
Use cases
How teachers use the vocabulary analyzer
Analyze essays and reading passages with Lexile levels, Academic Word List coverage, and Tier 2 vocabulary detection. Designed for teachers, literacy coaches, and students.
Conference about an essay draft
Paste a draft. The Lexile band tells you reading-level complexity. The Tier 2 list shows which strong academic words the writer already controls, and which they are reaching for but using inexactly. Useful in a student conference or a self-revision pass before turning it in.
Plan a reading passage
Paste a passage you are considering for a unit. The Lexile band tells you if it fits your students. The AWL coverage tells you how much academic-language scaffolding the passage will need. Pair with CoGrader's reading level converter when a passage runs too high.
Build a word study
Run a chapter through the analyzer. The Tier 2 list is your starting vocabulary set for the week. Beck and her co-authors recommend 5 to 8 Tier 2 words per text; the analyzer surfaces 10 to 20 candidates so you can pick the ones that matter.
Built for K-12 teachers
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Frequently Asked Questions
Built for K-12 teachers and students.
Is the vocabulary analyzer really free?
Yes. The analyzer is free, requires no account, and has no usage limit for normal use. CoGrader's full essay-grading platform is the paid product. The free tools exist so teachers and students can try CoGrader's research without a signup wall.
Do I need to create an account to use it?
No account, no email, no signup. Paste your text and analyze. The tool runs through CoGrader's vocabulary API. If you want to save analyses across sessions or batch-grade essays, the full platform handles that, but the analyzer itself stays open and accountless.
Is the text I paste here stored or used to train AI?
No. Text pasted into the analyzer is used for that single analysis and is not stored long-term, shared with third parties, or used to train any AI model. Both teachers and students can paste student writing without creating a record of it outside their own download.
What is a Lexile measure and how is it calculated?
A Lexile measure scores text difficulty on a scale from about 200L to 1600L. It combines word frequency (how common the words are in published English) and sentence length (a proxy for syntactic complexity). MetaMetrics created the framework. Our value is an estimate, useful for instructional decisions.
What is the Academic Word List, and what's a good AWL percentage?
The Academic Word List is 570 word families that show up across academic writing in every discipline (Coxhead, 2000). Casual writing usually scores under 4% AWL. Strong middle school and high school academic writing typically lands between 6% and 12%. Above 15% usually signals scholarly text.
What are Tier 2 vocabulary words?
Tier 2 words are high-utility academic words that show up across subjects but rarely in casual speech (Beck, McKeown, Kucan, 2002). Words like demonstrate, perspective, contribute, evaluate. They are the words most worth teaching directly because students need them everywhere, across every subject.
I'm a student. How do I use this to improve my own writing?
Paste your draft essay. Aim for AWL coverage above 6% for middle school work and above 8% for high school. Replace casual hedges like "a lot of" or "really" with the Tier 2 candidates in the result list. Compare drafts side by side to see your academic vocabulary growing.
Can I use this for ESL or ELL students?
Yes. Lexile and AWL signals translate well to multilingual learner contexts, and the highlighted view shows which academic words a learner already controls. For pure CEFR-banded analysis, Text Inspector and Cathoven are stronger. For K-12 classrooms in the U.S., the three-framework view here is more useful.
How does this compare to CoGrader's AI essay grader?
The vocabulary analyzer measures the words. The AI essay grader scores the whole essay against a rubric, including vocabulary, organization, evidence, and conventions, with feedback for the student. Teachers use the analyzer for quick checks and the essay grader for full grading workflows.