The English Vocabulary Profile is an online vocabulary resource for teachers, teacher trainers, exam setters, materials writers and syllabus designers. It offers extensive information about the Common European Framework of Reference (CEFR) levels of words, phrases, phrasal verbs and idioms, and currently includes just under 7,000 headwords. This article reports on the trialling and validation phase of the A1−B2 levels of the resource, as well as outlining the research and completion of the C1 and C2 levels. The project has followed a ‘can-do’ rationale, focusing on what learners actually know rather than prescribing what they should know, and is underpinned by up-to-date corpus evidence, including the 50-million word Cambridge Learner Corpus and the 1.2-billion word Cambridge English Corpus of first language use. At C1 and C2 levels, the English Vocabulary Profile describes both General and Academic English, and the additional sources used to research this area of language learning are described in the article. Polysemous words are treated in depth and the project has sought to determine which meanings of these important words appear to be acquired first; new, less frequent meanings often continue to be learned across all six CEFR levels. Phrases form another substantial part of the resource and this aspect has been guided by expert research (see Martínez 2011).