VocabularySize.com

Test interface

English language learners can measure the size of their English vocabulary at VocabularySize.com.

There is an online test of 140 questions. Teachers can create class tests.

It has been claimed that you need to know at least 98% of the words in a text to be able to understand it fairly easily. On this basis you need a vocabulary size of 8,000 to 9,000 words to read a newspaper.