How many English words does the average person know?

One large study estimated that a typical 20-year-old native speaker of American English recognised about 42,000 lemmas, derived from about 11,100 word families. Those are two ways of counting the same vocabulary. Neither is a universal average for everyone who speaks English.

For a quick estimate of your own vocabulary, try our free browser vocabulary test. It takes about two minutes. Check its counting method before comparing the result with a research figure.

Why you see both 42,000 and 11,100 words

Brysbaert, Stevens, Mandera and Keuleers reported these estimates in their 2016 vocabulary study. Their results depend on how entries are grouped:

Counting unit	Estimate for a 20-year-old native speaker
Lemmas	About 42,000
Base words / word families	About 11,100

A lemma groups a base word with its inflected forms. A word family can group related derived words too. For example, help, helps and helped can share a lemma, while helpful can belong to the broader family. The family total is smaller because more entries are grouped together.

The study measured recognition, which could be as limited as knowing that a word exists. It did not establish that participants could define every word, spell it correctly or use it naturally in conversation. Its population and counting rules matter when interpreting the numbers.

For the age comparison and why children’s checklists need separate treatment, see average vocabulary size by age.

How many words do English learners know?

There is no single useful average covering a beginner, someone studying for an exam and someone who uses English at work every day. A test also needs to specify whether it measures recognition, understanding a meaning or producing a word without a prompt.

Imagine that you recognise reluctant in “She was reluctant to leave.” Can you explain the sentence? Could you use reluctant while describing a decision of your own? Those questions ask for different kinds of knowledge, even though they concern one word.

The Council of Europe’s CEFR levels describe language abilities. They do not assign a required English word count to each level. A vocabulary estimate cannot certify B2, C1 or any other level. Our B2 vocabulary guide explains one research scale and why its figures are not total vocabulary counts.

What does a vocabulary size test actually do?

A short test samples vocabulary rather than asking about every word. Its result therefore depends on the sample, the scoring method and how you decide which items you know. A few different answers can move the estimate.

Our English vocabulary test samples six study bands and mixes in invented words to flag overclaiming. It gives an informal word-count estimate and a suggested study band. There is no validated error margin, and the band is not a language qualification. Your answers and score stay in the browser; no account is needed.

When answering, use one standard throughout. Do not select a word merely because its spelling looks familiar. If you repeat the test, avoid rehearsing the exact items first: remembering a checklist is different from learning vocabulary you can use elsewhere.

Use the result to choose something to practise

Open one of our A1 to C2 word lists and read a short section. For each unfamiliar entry, cover the definition and work from the example. Then write a sentence about something you have done or want to explain.

If almost every entry is unfamiliar, try an easier list. If you can explain them comfortably, move on. The labels organise our practice selections; they do not turn the list into an official CEFR syllabus.

For regular practice on your phone, the English Vocabulary Size Test Android app has illustrated exercises and a review deck. The core test is free; an optional upgrade adds full history and unlimited daily reviews. Browser answers are not transferred into the app.

The next time you read in English, save a sentence that held you up. Practise the unfamiliar word in that sentence, then try to explain it without looking.