www.testyourvocab.com
www.shanbay.com/vocabtest/welcome/
http://my.vocabularysize.com/
According to the last website:
| Skill | Size estimate | Notes |
|---|---|---|
| Reading | 8,000 - 9,000 word families | Nation (2006) |
| Listening | 6,000 - 7,000 word families | Nation (2006) |
| Native speaker | 20,000 word families | Goulden, Nation, & Read (1990) Zechmeister, Chronis, Cull, D’Anna, & Healy (1995) |