How Many Words Does the Average Person Know? About 42,000
The best large-scale estimate says the average 20-year-old native speaker of American English knows about 42,000 words (counted as lemmas, so “run”, “runs” and “ran” count once). The range is wide: about 27,000 for the lowest 5% and 52,000 for the highest 5%. By age 60, the average rises to about 48,000.
Key facts
- Average 20-year-old: about 42,000 words. Lowest 5%: 27,000. Highest 5%: 52,000.
- Average 60-year-old: about 48,000 words.
- Between 20 and 60, people learn about one new word every two days.
- For comparison, our random word list has 18,745 words; an average adult knows more than twice that.
How the study worked
Researchers led by Marc Brysbaert at Ghent University built a list of 61,800 English lemmas and ran an online test in which people said which words they knew, with made-up “non-words” mixed in to catch guessing. Close to a million people took the English test. The results were published in Frontiers in Psychology in 2016.
Knowing a word is not one thing
The study counted words people recognise. Using a word confidently in speech or writing is harder, and most people use far fewer words than they know. It also helps to remember that common words carry many meanings: in our own analysis, an easy English word has 7.0 meanings on average.
How vocabulary grows
The same study estimated that a 20-year-old knows about 11,100 word families (a base word and its relatives), which works out to roughly 1.7 new base words a day from age two. After 20, learning slows to about one new word every two days, mostly through reading.
Ways to keep growing yours
- Read widely. Most new words come from reading, especially outside your usual topics.
- Meet one new word a day. Our word of the day gives you a medium-difficulty word with a meaning and example.
- Practise rare words on purpose. The vocabulary word generator serves less common words with meanings, good for a quick daily quiz.
- Space it out. Seeing a word again a few days later helps it stick much better than cramming.
Sources
- Brysbaert, M., Stevens, M., Mandera, P. and Keuleers, E. (2016). How Many Words Do We Know? Practical Estimates of Vocabulary Size Dependent on Word Definition, the Degree of Language Input and the Participant’s Age. Frontiers in Psychology 7:1116.
- Most adults know more than 42,000 words, Frontiers news (2016).
