CSV Deduplicator
Remove duplicate rows from CSV files. Select columns for comparison and export clean, unique data. Process structured data directly in your browser with no file uploads to servers..
Upload a CSV to Deduplicate
Select which columns to check for duplicates and remove them instantly.
What is CSV Deduplicator | Rune
CSV Deduplicator removes duplicate rows from your CSV data based on selected columns. Choose which columns to check for duplicates, preview results, and download the cleaned data, perfect for data cleaning, mailing list dedup, and database preparation.
Handles complex data structures with nested objects, arrays, and special characters without data loss. Supports large files with optimized parsing that processes thousands of records efficiently. Preview converted data in a formatted view before downloading or copying to your clipboard. This tool runs entirely in your browser, requiring no software downloads or installations on your device.
Key Features of CSV Deduplicator
Everything you need for professional csv deduplicator
Column Selection
Choose which columns to use for duplicate detection, check all columns or just specific ones.
Smart Deduplication
Keeps the first occurrence of each unique row and removes subsequent duplicates.
Duplicate Statistics
See how many duplicates were found and removed with clear before/after counts.
Preview Results
View the deduplicated data in an interactive table before downloading.
Download Clean CSV
Export the deduplicated data as a clean CSV file ready for use.
Privacy Safe
All processing happens locally in your browser. Your data never leaves your device.
How to Use CSV Deduplicator
Follow these simple steps to get started
Upload CSV
Upload a .csv file or paste CSV data containing duplicate rows.
Select Columns
Choose which columns to check for duplicates. Select all or specific columns.
Download Clean Data
Review the results and download the deduplicated CSV file.
Pro Tips
- Select only key columns (like email or ID) to remove duplicates based on specific fields, not entire rows.
- Use 'Select All' to find exact duplicate rows across every column.
- Check the statistics to understand how much redundant data was in your file.
- Combine with our CSV Sorter to organize your cleaned data after deduplication.
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Frequently Asked Questions
Everything you need to know about CSV Deduplicator
How does deduplication work?
The tool compares rows based on selected columns. When two or more rows have identical values in those columns, only the first occurrence is kept.
Can I deduplicate by specific columns?
Yes, select any combination of columns for comparison. For example, deduplicate by email only while keeping different names.
Which duplicate is kept?
The first occurrence (earliest in the file) is kept, and subsequent duplicates are removed.
Is my data safe?
Yes. All processing happens in your browser. No data is sent to any server.
Is there a row limit?
No hard limit. The tool runs in your browser, so performance depends on your device. Files with tens of thousands of rows work smoothly.
Does it handle case sensitivity?
The comparison is case-sensitive by default, 'John' and 'john' are treated as different values.
Is CSV Deduplicator free?
Yes! CSV Deduplicator is 100% free with no limits. Remove duplicates from your CSV data as often as you need without creating an account.
Can I preview duplicates before removing them?
Yes, the tool shows you exactly how many duplicates were found and lets you preview the cleaned data before downloading, so you always stay in control.
Still need help?
Can't find what you're looking for? Our support team is here to assist you.
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