Duplicate Word Finder
Use the CaseSwitch Duplicate Word Finder to list words that appear more than once, with counts, so you can cut filler and accidental doubles before you publish. Paste a paragraph or page, read the ranked repeats, and revise. Analysis runs in this browser — nothing is uploaded.
Written by the CaseSwitch editorial team. We maintain these tools in the browser so drafts, keys, and images stay on your device.
Last reviewed: 23 July 2026
Processed locally in your browser. Nothing is sent to a server.
Paste or type text to convert. Output stays empty until there is input.
Character count: 0 · Word count: 0 · Line count: 0
Examples
Repeated content words
Input
the the quick fox fox fox
Output
fox: 3 times the: 2 times
Case-insensitive grouping
Input
Tool tool TOOL
Output
tool: 3 times
Punctuation stripped from tokens
Input
cloud, cloud. Cloud!
Output
cloud: 3 times
No duplicates
Input
unique words only
Output
No duplicate words found.
Contractions kept as one token
Input
It's it's fine fine
Output
it's: 2 times fine: 2 times
How to use
- Paste the draft, email, or caption into the input panel.
- Read the duplicate list on the right. Highest counts appear first.
- Edit the source for content words you overused; ignore ordinary function words unless they are accidental doubles.
What this tool is for
Writers hammer the same adjective; drafts hide “the the”; landing pages overuse a product name. This tool tokenizes your paste, lowercases each word, and reports only tokens that appear more than once — with how many times. It is a writing aid and a quick QA check, not a plagiarism scanner and not a full frequency table of every word including singles.
How it works
Words are matched with a word-boundary pattern that keeps letters, digits, and apostrophes inside a token (`\b[\w']+\b`). Each token is lowercased for counting, so “Tool”, “tool”, and “TOOL” share one key. Only keys with count greater than one are listed, sorted by count descending. Each line looks like `word: N times`. If nothing repeats, the output is exactly “No duplicate words found.” Trailing punctuation is not part of the token, so “cloud,” and “cloud” group together.
When to use it
Editing blog posts, reviewing ads copy, checking whether a product name is overused, hunting accidental double words, and tightening a paragraph before a character limit. Pair with the Word Frequency Counter when you also need singles and a full ranked list.
When not to use it
This is not a plagiarism checker and not an SEO crawler. It will not score keyword clusters or search volume. For every token including those that appear once, use the Word Frequency Counter. For whole-line uniqueness, use the Duplicate Line Remover.
How it compares to related tools
The Word Frequency Counter lists every token that meets the minimum length. The Word Cloud is a text ranking of frequent terms. The Duplicate Line Remover works on whole lines. Use this finder when you only care about repeats inside running prose.
Common mistakes
Panicking because “the” and “and” appear often — they should. Treating a company name and a common noun as a problem without reading context. Expecting hyphenated compounds to always stay one token when the pattern splits on non-word characters. Assuming case differences create two keys (they do not).
What counts as a word
The matcher keeps apostrophes inside tokens, so contractions stay whole. Hyphens are not word characters here, so “state-of-the-art” may split around the hyphens depending on the engine’s `\w` definition. Digits inside tokens are kept. Empty input produces the “No duplicate words found.” message because there are no repeating keys.
Editing with the list
High counts on articles and prepositions are normal English. Focus on verbs, adjectives, and brand names you did not intend to hammer. Accidental doubles (“the the”) show up with count 2 and are usually a one-character delete. For a sortable table of every word, switch to the Word Frequency Counter and raise minimum length to hide short function words.
Frequently asked questions
Are common words like “the” listed?+
Yes if they repeat. High counts on articles are normal. Focus on content words you did not intend to overuse.
Is matching case-sensitive?+
No. Tokens are lowercased before counting, so “Apple” and “apple” share one key.
Does punctuation create a separate word?+
No. Trailing commas and periods are outside the token, so “cloud,” and “cloud” count together.
What if nothing repeats?+
The output is exactly “No duplicate words found.” That is success, not an error.
How is this different from word frequency?+
Frequency lists every token (including singles). This finder only prints words that appear more than once.
Is my text uploaded?+
No. Counting runs in this browser. Drafts stay on your device.
Does CaseSwitch upload this text?+
No. Conversion, cleaning, and counting for this page run in your browser. Drafts are not sent to CaseSwitch for processing.
Related tools
Word Frequency Counter
Checking an essay against a word limit, counting characters for a caption or meta description, spotting a word you used too often, comparing two drafts by pasting them one after the other, and preparing a keyword list after you have already written the copy (not the other way around). The [Sentence Counter](/online-sentence-counter/) is a sibling if you only want the totals without a frequency table. The [Word Cloud](/word-cloud-generator/) is a text ranking of the same counts, not a picture.
Duplicate Line Remover
Deduping email lists, unique-ifying a keyword list, cleaning a changelog pasted twice, preparing a column for import, and removing repeated headers from a log extract. Use it when duplicates are exact line repeats and you want to keep original order. Pair with the Whitespace Remover first if trailing spaces or mixed tabs make visually identical lines look different to you but not to the tool.
Sort Words Alphabetically
Tag lists, glossary drafts, comparing two versions of a keyword set, preparing alphabetical credits, and stabilizing a permission list before diff.
Sentence Counter
School assignments, social captions with limits, checking whether a paragraph is too long, comparing two drafts, and getting a quick structure snapshot before you open a full word processor.
Text Frequency Cloud
Skimming a long interview, spotting repeated talking points, teaching frequency without a design tool, and getting a fast visual before you open the full frequency table.