The Average 20-Year-Old American Knows 42,000 Words, Claims Study - How Do You Compare?


Tom Hale


Tom Hale

Senior Journalist

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist



Language experts have always struggled to estimate the size of people's vocabulary. But now researchers have been dipping into a huge pool of information collected through social media in a bid to settle a piece of the debate.

The psychologists from Ghent University in Belgium found that an average 20-year-old native English-speaking American knows 42,000 dictionary words. Their findings were recently published in Frontiers in Psychology.


Around one million participants took part in the test, which was widely distributed and shared through Facebook and Twitter. Who knows, you might have been a part of the study. It was intentionally kept simple and could be done in just four minutes. You can take the test yourself here.

It asked participants if the word on the screen was a word in the English dictionary, with the data using a pick of 62,000 words. In the test, the participants were shown 70 actual words and 30 fake words. It then asked some basic information about the participants like age, gender, education, and native language. 

Using this information, they could then create an estimate of how many words that person knows. According to the researchers, their data also showed that we learn around one new word every two days. So our vocabulary grows to around 48,000 words by the time we're 60 years old.

"This work is part of the big data movement in research, where big data sets are collected to be mined." lead author Professor Marc Brysbaert of Ghent University said in a press release.


"It also gives us a snapshot of English word knowledge at the beginning of the 21st century. I can imagine future language researchers will be interested in this database to see how English has evolved over 100 years, 1,000 years and maybe even longer".


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  • language,

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  • words,

  • facebook,

  • survey,

  • dictionary,

  • vocabulary