How Many Words Are in English? Real Numbers and Why It Depends

You have probably seen every answer from 170,000 to 1,000,000+ when you ask how many words are in English. The problem is not the math, it is the definition: are we counting dictionary entries, word forms like run/runs/running, technical names, slang, or phrases?

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Quick answer (use the right number for your goal)

Big-dictionary size: The Oxford English Dictionary describes itself as featuring 600,000 words, and Cambridge notes it has over 600,000 entries. ([oed.com][1])
Total English vocabulary: Some estimates put English at roughly 1 million words, but even Merriam-Webster says that number is uncertain and could be off by hundreds of thousands (especially once you include scientific names). ([Merriam-Webster][2])
What one person knows: Research-based estimates for adult native speakers vary by how you define a word (lemmas vs word families), but it is typically in the tens of thousands. ([Frontiers][3])

Counts change over time. Dictionaries add and remove entries regularly, so treat any number as a snapshot and check the dictionary publisher for the latest. ([AP News][4])

What counts as a word (and why answers disagree)

Most pages that rank for this question mix categories without saying so:

Headword: the main entry in a dictionary (for example, run).
Word form: inflected versions (run, runs, running, ran) and sometimes derivatives.
Lemma: a base form used in linguistics (often similar to a headword).
Word family: a base plus transparent relatives (happy, happiness, happily). Word-family counts are common in vocabulary research. ([ScienceGuide][5])
Multiword expression: fixed phrases (by the way, in spite of) that behave like a single unit in meaning.

On top of that, you have choices about scope: do you include proper nouns, dialect words, slang, brand-new compounds, and scientific terminology? David Crystal points out that compounds and specialized vocabularies alone make a complete count impossible. ([Cambridge Assets][6])

The 3 most useful numbers (dictionary, language, and person)

1) Dictionary size: how many entries does a major dictionary record?

If you need a grounded, citeable number, dictionary size is the easiest. The OED is commonly referenced as having 600,000+ entries/words (depending on how entries and word-forms are counted). ([oed.com][1])

2) Language size: how many words exist in English overall?

This is where the internet gets messy. One widely repeated idea is that English has about 1 million words, but that usually relies on generous counting (technical names, rare coinages, and lots of low-frequency items). Merriam-Webster explicitly treats the 1 million figure as a rough, uncertain estimate. ([Merriam-Webster][2])

3) Personal vocabulary: how many words does an English speaker know?

For writers and students, this is often the number that matters. Brysbaert and colleagues (2016) estimate that an average 20-year-old native speaker knows about 42,000 lemmas, with a wide range across people, and vocabulary continues to grow with age. ([Frontiers][3])

In word-family terms, Paul Nation summarizes research suggesting well-educated native speakers know around 20,000 word families (and you can think of each family as several related word forms). ([ScienceGuide][5])

Table: pick the right word-count number

Word Count Reference Table

Use case	What you are counting	Typical figure	Why it helps
Citing a dictionary-based figure	Entries/words in a major dictionary	600,000+ (OED)	Grounded, publishable, and easy to source
Talking about all English words	Everything, including technical names and rare coinages	About 1 million (very rough)	High-level trivia only; extremely definition-dependent
Describing a person's vocabulary	Word families or lemmas (not raw word forms)	About 20,000 word families or about 42,000 lemmas	Closest to real-world language ability
Meeting a word limit for a draft	The word count of your actual text	Your draft (count it)	Most useful for publishing, essays, ads, and captions

How to estimate word counts for your own project (no special tools)

Write down your definition. Decide: headwords, lemmas, word families, or word forms.
Choose your scope. Standard English only, or include dialects, slang, technical names, and compounds?
Pick your reference. A dictionary for entries, or a corpus for usage (news, books, web).
Count consistently. If you count word forms, do it everywhere; if you count families, do it everywhere.
Document your assumptions. One sentence in your report explaining what you counted makes your number credible.

If you mainly care about writing limits, start with the practical metric: the word count of your actual text. For the basics on counting words and characters (including tricky cases like hyphens and emojis), see Character count basics and our hub of Writing tools.

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Paraphrase, shorten, or expand copy to fit word and character limits without losing your meaning.

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Mistakes to avoid (common traps)

Treating dictionary size as total English. No dictionary can capture every slang term, compound, scientific label, or regional coinage. ([Cambridge Assets][6])
Mixing word forms and headwords. Saying run and running are two words in one paragraph and one word in the next makes comparisons meaningless.
Quoting the 1 million number as a fact. It can be a useful ballpark, but it is definition-dependent and uncertain. ([Merriam-Webster][2])
Ignoring time. Dictionaries add thousands of new entries over time, and older counts can be outdated. ([AP News][4])
Confusing passive and active vocabulary. People usually recognize far more words than they actively use. ([Cambridge Assets][6])

FAQ

How many words are in the Oxford English Dictionary?

It depends on what you call a word, but reputable references describe the OED as having 600,000+ words or entries. ([oed.com][1])

So is English really a million words?

Some estimates land around 1 million when they include technical names and rare items, but major dictionary editors warn the figure is uncertain and highly sensitive to definitions. ([Merriam-Webster][2])

How many words does an average native speaker know?

Research varies by method. One large study estimates around 42,000 lemmas for an average 20-year-old native speaker, while other approaches summarize knowledge as roughly 20,000 word families for well-educated adults. ([Frontiers][3])

How many words do you need to be fluent?

Fluency is about coverage and practice, not reaching some total. Many learners aim to master high-frequency vocabulary first, then expand through reading and speaking in the domains they care about.

How many new words get added each year?

There is no single annual number for English, but major dictionaries add thousands of new entries or updates in big revisions. ([AP News][4])

Do slang and compound words count?

They can, but they are hard to track. Many compounds are understandable from their parts and never make it into dictionaries, and slang changes faster than lexicographers can record. ([Cambridge Assets][6])

A practical next step for writers

If your real goal is not trivia but better writing, focus on the counts you can control: the word count of your draft, and whether it says what you mean in fewer (or clearer) words.

One low-friction way to do that is to rewrite and tighten sentences without changing meaning. If that is useful, paraphrase and polish your text to fit a target word count with QuillBot.

Conclusion

There is no single, final number of English words because English is not a fixed list. Use 600,000+ when you need a dictionary-based figure, treat 1 million as a debated upper-bound estimate, and use tens of thousands when you are talking about what a person knows. Then, for anything you publish, rely on the word count of the text in front of you.