Unique Word Counter — Free Online Tool
What is Unique Word Counter?
The Unique Word Counter (also known as a vocabulary richness analyzer) scans your text and identifies exactly how many distinct, unique words were used. If you type 'the cat chased the dog', the normal word count is 5, but the unique word count is 4 (because 'the' is repeated).
This metric, often called lexical diversity, reveals the breadth of your vocabulary. It is a powerful tool for authors, essayists, and language learners looking to avoid repetitive phrasing and ensure their writing is vivid and diverse.
When to use Unique Word Counter?
Use the Unique Word Counter to assess your writing style and remove repetitive phrasing. Novelists and creative writers use it to ensure they aren't leaning on the same adjectives to describe scenes. SEO writers use it to measure topical depth—a higher ratio of unique keywords suggests broader coverage of a topic, which search engines favor.
Language learners use it to measure their expanding vocabulary. If you find highly repetitive words, you can use the Find and Replace Text tool to swap them for synonyms.
How to use this tool
- 1Paste your text in the input area
- 2Click 'Analyze' to count unique words
- 3View unique word count and vocabulary richness percentage
The tool normalizes the text before counting: it converts everything to lowercase and strips punctuation, ensuring that 'Apple', 'apple', and 'apple,' are correctly identified as the same unique word.
Examples
| Input | Output |
|---|---|
| The cat sat on the mat. | 5 unique words (the, cat, sat, on, mat) | Richness: 83% |
| (1000-word article) | Typically 400-600 unique words | Richness: 40-60% |
| (Academic paper) | High unique word count indicates diverse vocabulary |
| (Marketing copy) | Low richness may indicate repetitive messaging |
| (Novel chapter) | Unique word rate shows writing style diversity |
Rules & Behavior
- All text is temporarily converted to lowercase for the calculation, meaning 'The' and 'the' are correctly grouped as one unique word.
- Punctuation attached to words is stripped away before counting so that 'word' and 'word.' are not treated as two different vocabulary items.
- Lexical Diversity is calculated by dividing the Unique Word Count by the Total Word Count, resulting in a percentage that represents vocabulary richness.
Related Tools
Frequently Asked Questions
What is the difference between total words and unique words?
The total Word Counter tells you the raw volume of your text (e.g., 'Run Forrest run' = 3 words). The Unique Word Counter tells you the vocabulary size (e.g., 'Run Forrest run' = 2 unique words, 'run' and 'Forrest').
What does 'Lexical Diversity' mean?
Lexical diversity is the mathematical ratio of unique words to the total word count. If a 100-word paragraph uses 75 unique words, its lexical diversity is 75%. Higher percentages generally indicate a broader vocabulary and less repetition, which makes creative writing more engaging.
Are capitalized words counted separately?
No. The tool is smart enough to temporarily convert all text to lowercase before running the analysis. This ensures that 'Apple' at the beginning of a sentence and 'apple' in the middle of a sentence are correctly grouped together as one unique root word.
How can this help with SEO?
Search engines like Google use natural language processing to understand context. If you write an article about 'coffee', utilizing a high number of unique, related words (espresso, beans, roast, brewing, robusta) signals to the algorithm that the article covers the topic with significant depth and expertise.
Does it count different forms of the same word?
Basic unique word counters treat 'run', 'runs', and 'running' as three separate unique words because they are spelled differently. For advanced linguistic analysis, a process called 'stemming' or 'lemmatization' is required, but standard tools look at the exact spelling.