📚Vocabulary Size Test

How many words do you actually know?

Take this free Vocabulary Size Test to estimate the size of your receptive English vocabulary. You will see a mixture of real English words and realistic-looking fake words. Mark only the words whose meanings you genuinely know.

The decoy words matter: selecting made-up words tells the test that guessing or familiarity may be inflating your result.

This is an approximate browser estimate based on a sample of words. It is not a complete count of every word you know.

How to Take the Vocabulary Size Test

1. 1Press Start Test.
2. 2Read every word carefully.
3. 3Mark a word only if you know what it means.
4. 4Leave unfamiliar words unmarked.
5. 5Do not select a word just because it looks or sounds real.
6. 6Submit the full list.
7. 7Review your estimated vocabulary size.

A useful rule is:

If you could not explain the basic meaning or use the word appropriately in a sentence, do not mark it as known.

There is no advantage to guessing. The test includes nonwords specifically to detect overconfident yes-responses.

What Does a Vocabulary Size Test Measure?

This type of test mainly measures receptive vocabulary breadth.

Receptive vocabulary means words you can recognize and understand when someone else presents them.

That is different from productive vocabulary—the words you can actively retrieve and use yourself in speech or writing.

Most people understand more words than they spontaneously produce.

A vocabulary-size estimate also says more about breadth than depth. Knowing that a word exists and having a rough grasp of its meaning is different from knowing:

• ✓every definition;
• ✓subtle connotations;
• ✓pronunciation;
• ✓grammatical behavior;
• ✓collocations;
• ✓register;
• ✓and how to use it precisely.

So “How many words do I know?” is not as simple as it sounds.

Why Fake Words Are Included

Imagine a test containing only real words.

If you mark every unfamiliar word as “known,” your score rises—even though your vocabulary did not.

Fake words, also called pseudowords or nonwords, help reveal that response bias.

A plausible decoy might look English enough that you feel you have probably seen it before. If you mark several such items, the test has evidence that some of your real-word selections may also have been guesses.

Research vocabulary tests and lexical-decision measures often use real words alongside nonwords for exactly this reason.

The goal is not to trick you.

It is to make “yes, I know this” more informative.

How Can a Short Test Estimate Thousands of Words?

No practical web test can ask you about every English word.

Instead, vocabulary tests use sampling.

A carefully selected sample contains words from different frequency or difficulty levels. Your responses are then used to estimate how much of a much larger vocabulary you are likely to know.

This is similar to estimating a large population from a sample rather than checking every individual.

But the quality of the estimate depends heavily on the sample.

A short list that overrepresents scientific terms, archaic words, American vocabulary, or one difficulty band could give a distorted result.

That is why your final number should be read as an estimate from this test's word sample, not a literal inventory of your mind.

What Counts as a “Word”?

This is the biggest reason vocabulary-size claims vary so widely.

Consider:

walk walks walked walking

Are those four words or forms of one underlying word?

Researchers use several definitions.

Word Type

Every distinct written form can be counted separately.

Lemma

Inflected forms are grouped under a base form. “Walk,” “walks,” “walked,” and “walking” may be treated as one lemma.

Word Family

Related derived words may be grouped even more broadly, depending on the rules used.

For example, a word-family approach may connect a base word with some predictable derivatives.

Different definitions produce very different totals.

So two websites can give you different vocabulary numbers without one necessarily being fraudulent—they may simply be counting different units.

How Many Words Does an Adult Know?

Large-scale English vocabulary research gives useful context, but the numbers must be interpreted carefully.

A widely cited 2016 study by Marc Brysbaert and colleagues estimated that the average 20-year-old native speaker of American English knew about 42,000 lemmas, with substantial individual variation.

Using the same framework, the researchers estimated about 48,200 lemmas around age 60.

Those are not universal cutoffs.

The estimates depended on:

• ✓how “word” was defined;
• ✓the participant population;
• ✓receptive recognition;
• ✓the underlying word list;
• ✓age;
• ✓and language exposure.

The same paper emphasized that vocabulary estimates are approximations and that receptive word knowledge is not all-or-nothing.

Do not use 42,000 as a pass/fail target for every English speaker.

Native Speakers vs. English Learners

A vocabulary-size result means different things depending on language background.

A native English speaker may have accumulated vocabulary across decades of conversation, education, reading, media, work, and hobbies.

An English learner may know fewer total English words while having excellent vocabulary in another language.

Multilingualism also complicates simple comparisons.

Research on large online vocabulary samples has found relationships between vocabulary size and factors including age, education, and multilingual language experience.

A lower English estimate is therefore not a measure of general intelligence or language ability.

It is specifically about English word knowledge in the tested sample.

Familiarity Is Not the Same as Knowledge

One of the hardest decisions in a yes/no vocabulary test is what to do with a word that feels familiar.

You may think:

“I know I have seen this somewhere.”

But can you explain what it means?

Recognition has degrees.

You might:

• ✓recognize the spelling;
• ✓know the general topic;
• ✓know one meaning;
• ✓know several meanings;
• ✓or be able to use the word naturally.

For this test, use a reasonably strict standard.

Mark a word when you know its basic meaning, not merely when it triggers a feeling of familiarity.

That makes your estimate more stable and reduces false positives.

Vocabulary Size vs. Verbal Memory

Vocabulary knowledge and verbal memory are different abilities.

The Verbal Memory Test asks whether you remember seeing a particular word earlier in the same session.

The Vocabulary Size Test asks whether you already know what a word means.

You can have a large vocabulary and still forget which words appeared a minute ago.

You can also have excellent short-term recognition memory while being unfamiliar with advanced vocabulary.

Do not compare the two scores directly.

Why Reading Is Strongly Connected to Vocabulary

Words are learned through exposure.

Conversation teaches many common words, but reading exposes people to a much wider range of low-frequency vocabulary.

Books, long-form journalism, technical material, and varied subjects repeatedly place unfamiliar words into meaningful contexts.

Large-scale vocabulary research has found that language exposure is strongly associated with vocabulary knowledge.

That does not mean simply seeing a word once guarantees learning.

Repeated encounters, meaningful context, retrieval, and actual use help turn a vague recognition into stronger knowledge.

How to Grow Your Vocabulary

Do not memorize random dictionary pages.

A better approach is to learn words in useful contexts.

Try:

• ✓reading material slightly above your comfortable level;
• ✓looking up words that repeatedly block understanding;
• ✓writing a short definition in your own words;
• ✓making a sentence using the word;
• ✓reviewing the word later;
• ✓learning common roots, prefixes, and suffixes;
• ✓and noticing how the word is actually used in real sentences.

Depth matters.

Learning ten words well is often more useful than briefly memorizing fifty definitions and forgetting them.

Frequently Asked Questions

Find Out What You Really Know

The most useful strategy is honesty.

Mark the words you truly understand.

Leave uncertain words alone.

Let the decoys do their job.

Your final number is not a complete dictionary of your mind—it is a sample-based estimate of receptive English vocabulary, useful for curiosity, comparison, and motivating further learning.