Find Duplicate Letters
Detect recurring characters in a string. Visualize repetition frequency and extract detailed stats.
Repeated Characters
Analysis Stats
Filters
Filter out characters appearing fewer times
Microscope for Your Strings
Finding repeated words is easy, but finding repeated characters requires a finer lens. The Find Duplicate Letters tool scans your text at the atomic level, instantly identifying every letter, number, or symbol that appears more than once. Whether you're debugging a string, optimizing a font, or solving a cryptogram, this tool reveals the hidden patterns in your data.
Analysis Features
Deep Scan
Detects every repetition, from standard letters to invisible whitespace and complex emojis.
Visual Charts
See repetition patterns at a glance with integrated frequency bars for top characters.
Smart Filters
Ignore numbers, punctuation, or whitespace to focus solely on the alphabetic characters.
Instant Stats
Get total char counts, unique counts, and redundancy ratios calculated in real-time.
100% Secure
Zero data collection. All analysis happens right in your browser for maximum privacy.
Export Data
Copy the list of duplicates or download a full report for your documentation.
Common Use Cases
- Programming: Find the first non-repeating character or debug string parsing logic.
- Cryptography: Use frequency analysis to crack substitution ciphers.
- Data Compression: Identify highly redundant characters to estimate compression potential.
- Design: Check if a font file is missing specific glyphs by analyzing sample text.
Frequently Asked Questions
What does this tool help with?
It identifies every character that appears more than once in your text. It's perfect for debugging code strings, solving word puzzles, or analyzing cryptographic patterns.
Does it count spaces?
Yes, by default spaces are treated as characters. However, you can enable the 'Ignore Whitespace' filter to exclude them and focus purely on visible letters and symbols.
Can I ignore numbers?
Absolutely. Use the 'Ignore Numbers' filter if you only want to find repeated alphabetic characters or symbols, keeping your analysis focused on text.
Is 'A' different from 'a'?
By default, no (Input is case-insensitive). However, you can toggle 'Case Sensitive' mode to treat uppercase and lowercase letters as distinct unique characters.
Can I upload a file?
Yes! You can upload .txt, .js, .json, or .css files to analyze entire codebases or documents for character repetition patterns.
How does the threshold work?
The 'Min Occurrence' slider lets you ignore characters that only repeat a few times. Set it to 3 or 4 to focus only on the most frequently repeated symbols.
Is my data private?
100%. All processing happens locally in your browser using JavaScript. No data is ever sent to a server.
Can I download the results?
Yes, you can download the full list of duplicate characters along with their counts and percentages as a text file for further analysis.
What is 'Dup Ratio'?
The Duplicate Ratio tells you what percentage of your text is made up of repeated characters compared to unique ones. Higher ratios indicate high redundancy.
Does it support Unicode/Emojis?
Yes, the tool fully supports Unicode, meaning it can detect and count repeated emojis, accented characters, and symbols from any language.