🧠Cerebite

Vocabulary Size Test

Check every word whose meaning you know. Be honest — a few made-up words are hidden in the list to keep everyone truthful.

Your vocabulary is about
0
words

Tap a word to mark it as known. When you're done, press "See my result".

How the estimate works

The English lexicon is sampled in frequency bands — from the 1,000 most common words down to extremely rare ones. You see a few random words from each band; the share you know in a band estimates how much of that whole band you know, and adding the bands up gives your total. Checking made-up words lowers the estimate, so honesty pays. Every retake draws a fresh random sample, so your number may vary by a couple of thousand — that's normal for a 2-minute estimate.

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Frequently asked questions

How accurate is this vocabulary test?
It's a statistical estimate from a 2-minute sample, not a full exam — expect a margin of a few thousand words. Taking it several times and averaging gives a steadier number. Research puts adult native speakers at roughly 20,000–35,000 words, which matches what this method reports.
Why are there made-up words in the list?
They're an honesty check. Self-reported tests are easy to inflate by checking everything — but fake words catch that, and each one you check lowers your estimate. If you avoid them all, your result is trustworthy.
What counts as "knowing" a word?
Check it if you could give at least one meaning of the word when you see it. You don't need to spell it from memory or use it actively — recognizing the meaning is the standard used by vocabulary researchers.