How a size estimate is produced
Nobody can be shown every word in English, so the test samples instead. The lexicon is divided into frequency bands — the thousand most common words, the next thousand, and so on down to the genuinely rare — and you see a small random selection from each. The share you recognise in a band is used to estimate how much of that whole band you know, and the bands are added together for a total.
The invented words are not a trick, they are the correction term. Every self-report test is inflated by words people half-recognise, and checking a word that does not exist is direct evidence of that happening. Ticking the fakes lowers your estimate, which is why honesty produces a higher and more useful number than optimism does.
What the numbers look like
Estimates for adult native English speakers usually land somewhere between twenty and thirty-five thousand word families, with wide variation by reading habit rather than by education alone. Learners of English as a second language commonly reach three to five thousand for comfortable conversation, and around eight to nine thousand is the range usually associated with reading unsimplified books and newspapers without constant lookups.
Treat any single result as approximate. Every retake draws a fresh random sample, so your number will move by a few hundred either way without anything having changed — which is a property of sampling, not a fault in the test. Averaging two or three attempts gives a steadier figure than any one of them.
The measure counts word families rather than individual forms. Knowing decide also credits you with decision, decisive and undecided, because someone who knows the base word can generally handle the rest.
Growing the number
- Read things slightly above your comfort level. Words met in context and repeatedly are the ones that stay.
- Look up only the words that block comprehension. Stopping at every unknown word turns reading into study and kills the volume that actually builds vocabulary.
- Learn word parts. Knowing that -ology is a study of and circum- means around unlocks dozens of words at once.
- Write new words in a sentence of your own. Producing a word once does more than recognising it ten times.
- Retest every month or two, not weekly. Vocabulary grows slowly enough that shorter intervals measure noise.
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.
How many English words do I need for each CEFR level?
Commonly cited benchmarks run from about 1,000 word families at A2, to around 2,500–4,000 at B2, and 8,000 or more at C1–C2, where reading newspapers and novels feels natural. Match your estimate from this test against those bands to see roughly where you sit — and what the next milestone is.
How fast does vocabulary grow naturally?
Native-speaking children pick up roughly 1,000 word families a year through their school years, mostly from reading — which is why vocabulary keeps expanding well into adulthood. For learners, steady reading plus deliberate study can approach that pace. Retest here every month or two; visible growth is normal on that timescale.
Does vocabulary size keep growing with age?
Yes — unlike many cognitive measures, vocabulary typically keeps increasing through adulthood and often peaks quite late in life, because every year of reading and conversation adds new words. So whatever your age, your estimate here isn't a ceiling: it's a snapshot of a number that's still moving.