English Vocabulary Test (adaptive)

An English vocabulary test of 108 items in two formats: for most you pick the word that matches a given meaning; for the harder ones you pick the two or three words out of five that are synonyms. The words are rare on purpose — this is a test of the top of the vocabulary range, not of everyday English.

Vocabulary is the single best short measure of general intelligence in adults who grew up speaking the language. The items were calibrated on 499 US adults recruited through Prolific in 2023, and your score is reported as an IQ relative to White US adults of your age (vocabulary keeps growing into the 60s, so the same score means less at 70 than at 25). If English is not your native language your score will mostly reflect exposure to it, not intelligence. The test's construction and validation are in Kirkegaard (2024), A New Open Source English Vocabulary Test.

This version is adaptive: after each answer the next item is chosen to be most informative at your estimated level. You get 25 items, and up to 5 more if the estimate is still imprecise. Untimed; most people take 5–8 minutes. The full 108-item version is the same pool given in full.