How many words does a B2 speaker know?

About 4,000 to 5,000 word families, roughly 6,500 to 10,000 individual words. That's enough for general conversation, opinions, and most everyday topics without constant searching.

On vocabulary tests that sample the 5,000 most common dictionary words, B2 learners score about 3,250 to 3,750. Every published number is real; they just count different things. That's why one article says 3,500 and another says 5,000.

Why every source gives a different number

The Common European Framework of Reference (CEFR) itself publishes no official word counts for any level, A1 through C2. Every number you'll find comes from vocabulary research, and the spread comes from the unit, not the research. Some studies count word families, some count lemmas (a dictionary headword plus its inflections), and some count every individual word. One family is roughly 1.6 to 2 individual words, so the same vocabulary produces very different totals depending on how you count.

The main measurements behind the numbers you'll see:

3,250 to 3,750 is Milton and Alexiou's measured band for B2 learners on the X_Lex test, which samples the 5,000 most common lemmas. It's a score out of 5,000, not a total vocabulary size.

4,000 to 5,000 word families is Paul Nation's suggested B2 range in his CEFR mapping. That range supports normal conversation on general topics.

4,000 words is the popular doubling-table figure for B2. It is an internet extrapolation, not a figure in the research. The table simply doubles its total at every CEFR level, and usually leaves the unit unclear.

Two caveats. These are receptive counts from English-language studies: passive vocabulary you recognize when reading or listening. The vocabulary you can actively use in speech is smaller. And educated native speakers carry well past 15,000 word families. B2 does not require a native-sized vocabulary; it requires reliable access to the words that general conversation uses most.

Does B2 vocabulary make you fluent?

Yes, with a qualification. Four to five thousand word families cover general conversation well, so B2 is a fair fluency threshold. But fluency is automatic access, not a count. If common words still arrive slowly, a larger vocabulary will not make speech flow. Hearing and using the high-frequency core until it becomes reflex will.

How many words do you need at the other levels?
See the real numbers for A1 · A2 · B1 · C1 · C2.

Sources: Milton and Alexiou, vocabulary size across the CEFR levels · Nation, Vocabulary and the CEFR · ILR, vocabulary size and reading coverage.