Free online English vocabulary size estimator using random sampling methodology. Supports multiple difficulty levels with detailed analysis reports and learning recommendations. 100% client-side.
Zero Dependency · Works OfflineThis is a practical online Vocabulary Builder. Operation is simple and intuitive. Just enter parameters and click run to get results. All calculations are done locally in your browser — no data is ever uploaded to any server, ensuring complete privacy.
This tool uses stratified random sampling: it draws test words from different frequency bands (1K, 2K, 3K words, etc.) and extrapolates your total vocabulary based on recognition rates. This method is much faster than testing every word and is statistically representative.
Native speakers: ages 4-5 ~5,000 words, adults ~20,000-35,000 words. English learners: middle school ~1,500, high school ~3,500, college CET-4 ~4,500, CET-6 ~6,000, TEM-8 ~10,000, GRE/TOEFL ~12,000-15,000. Daily conversation needs ~3,000 words; fluent reading needs ~8,000-9,000.
1) Learn 10-20 new words daily, review with spaced repetition; 2) Read extensively in English (news, novels, academic papers); 3) Study word roots and affixes (e.g., un-/re-/-tion) — one root unlocks many words; 4) Learn in context, don't memorize isolated words; 5) Use new words in sentences or writing.
This reflects the gap between 'passive vocabulary' (words you can understand) and 'active vocabulary' (words you can use). Passive vocabulary is typically 1.5-2x larger than active. To convert passive to active, deliberate practice is needed: write sentences, short essays, and use new words in conversation. Output practice is key.