How many words do you know? — the Lexicon guide

Lexicon estimates how many English words you know from a short, gorgeous checklist. Here is what the number means, how it is calculated, and how to get an honest result.

How many words does the average person know?

A widely-cited figure from vocabulary research is that a typical adult native English speaker knows roughly 42,000 lemmas (dictionary base words) by age 20 — the headline result of a large 2016 crowd-sourced study by Brysbaert and colleagues. Estimates vary a lot with how you count (word families, inflections, names and phrases push it higher; a stricter definition pulls it down), so treat 42,000 as a friendly anchor, not a hard fact. Lexicon caps its own estimate at 50,000 words, the top of that believable range.

What is Lexicon?

Lexicon is a free, two-minute browser test of vocabulary size. It is not a quiz with right and wrong answers: you simply mark the words you genuinely know from a fixed list. The catch is that the list mixes real English words with invented pseudowords — strings that look and sound plausible but are not real. Marking those gives you away, and the score corrects for it, so honesty beats bluffing.

How to play

1. You see a grid of about 60 words — 45 real ones and 15 fakes, shuffled.
2. Tap every word you truly know the meaning of. Tap again to un-mark.
3. Optionally pick your age band so the comparison is fairer — or skip it.
4. Tap See my result to get your estimated word count, your percentile, a tier, and the rarest word you knew.
5. Download or share your result card, or tap Test again for a fresh pack of words.

How the score works

The real words are sorted into five frequency bands, from very common to genuinely rare. Each band stands for a slice of the language, so knowing rare words is worth far more than knowing common ones. Lexicon works out how well you did in each band, then subtracts a guessing penalty based on how many fake words you fell for. If you mark a lot of pseudowords, your estimate drops and Lexicon flags the result as unreliable. Mark every word on the board and you score zero — a pure guesser knows nothing.

Tips for an honest score

• Only tap words you can actually define or use in a sentence — a vague feeling that you have seen it is not knowing it.
• Beware the plausible fakes. If a word looks real but you cannot place its meaning, leave it — it may be a trap.
• Do not rush the rare band. The rarest words swing your estimate the most, so give them a moment.
• Set your age band for a fairer comparison; vocabulary tends to grow for decades.
• Play a few packs. Lexicon ships five packs of 60 words and no word appears in more than one, so five runs judge you on 300 different words. Each pack samples the language differently, and an average across two or three runs is a steadier picture than a single one.

Is it accurate?

This is a fun estimate, not a scientific test. Your real vocabulary depends on how you define “knowing” a word — Lexicon gives a playful ballpark from a short sample, not a validated measurement. The bands and percentiles are our own editorial calibration tuned to feel credible and entertaining, not a psychometric norm. Enjoy the number, share the card, but do not put it on your CV.

FAQ

Is it free? Yes, completely, with no account or sign-up.

Do you store my answers? No. The whole test and its scoring run in your browser; nothing you tap is ever sent to a server. See the privacy policy.

Can I share my result? Yes — download the result card as an image or use your device’s share sheet.

Why did I score zero? You probably marked too many made-up words. The guessing correction zeroes out a run that trips every trap.

Will I see the same words again? Not for a while. There are five packs in rotation and they share no words at all, so you can take the test five times before any word comes back around.