Overview
Introduction
Repeated words are one of the easiest things to miss while editing your own writing, since the eye tends to skim past a word it just read.
This tool finds every repeated word for you instantly, and it runs entirely client-side, so nothing you paste is ever uploaded to a server.
What Is Duplicate Word Finder?
A finder that lists every word occurring more than once in your text, case-insensitive, each with its occurrence count, in the order each word first appears.
It runs entirely client-side as part of this site's String Tools collection, so nothing you paste is ever uploaded to a server.
How Duplicate Word Finder Works
The text is split into whitespace-separated words, each is lowercased for counting while its first-seen original casing is remembered, and any word whose total count is greater than one is listed as 'word: count' in first-appearance order.
The transformation happens synchronously in JavaScript the moment you type, with no network round trip involved.
When To Use Duplicate Word Finder
Use it while editing to catch unintentionally repeated words, or to analyze which terms a piece of writing leans on most heavily.
It's a fast way to get the answer without opening a spreadsheet or writing a one-off script just to check.
Often used alongside Unique Word Finder, Top Word Finder and Word Counter.
Features
Advantages
- Case-insensitive matching avoids treating 'The' and 'the' as separate words.
- Shows the exact occurrence count for each repeated word, not just a yes/no flag.
- Remembers the first-seen casing of each word, so the report shows the form you actually wrote rather than a lowercased version of it.
Limitations
- Splitting on whitespace means attached punctuation makes 'word' and 'word,' count as different tokens.
- Counts across the whole text at once, so it cannot show which paragraph or sentence a repetition is concentrated in.
Examples
Best Practices & Notes
Best Practices
- Strip surrounding punctuation first with a tool like Find and Replace if you want words like 'end' and 'end.' to be counted together.
- Look past the expected high counts for function words like 'the' and 'of', and focus on repeated content words instead.
- Run it per paragraph rather than across a whole document when editing for style, since it is local repetition that actually reads badly.
Developer Notes
Words are split with `input.trim().split(/\s+/)`, tallied by lowercase key in a `Map<string, number>` while a separate map remembers each key's first-seen original form, then keys with a count greater than 1 are formatted as `word: count` in first-appearance order.
Duplicate Word Finder Use Cases
- Catching accidentally repeated words while self-editing
- Analyzing which words a piece of writing relies on most
- Reviewing generated or translated text for over-repeated terms
Common Mistakes
- Expecting punctuation-attached tokens like 'end.' to merge with 'end'; they're counted as separate words.
- Treating a high count as automatically a problem; articles and prepositions repeat constantly in perfectly normal prose.
Tips
- Use the Unique Word Finder alongside this tool to see the full picture: which words repeat and which appear only once.
- Hyphenated compounds count as a single word because splitting is on whitespace alone, so 'well-known' never merges with 'known'.