Free CSV Editor: Edit CSV Files Without Spreadsheet Corruption

The Problem with Spreadsheet Applications as CSV Editors

Microsoft Excel and Apple Numbers are not CSV editors—they are spreadsheet applications that can open CSV files. This distinction matters because spreadsheet applications silently corrupt CSV data in ways that are difficult to detect:

Scientific Notation Conversion

Spreadsheets automatically convert large numbers to scientific notation. A value like 123456789012 becomes 1.23457E+11 when saved back to CSV—permanently losing precision.

Leading Zero Removal

ZIP codes, account numbers, and product codes with leading zeros are silently stripped. 00123 becomes 123—a data integrity failure that can break downstream systems.

Date Format Changes

Spreadsheets reformat dates according to your locale settings. An ISO 8601 date like 2026-02-20 may be saved as 2/20/2026 or 20-Feb-26, breaking date parsing in downstream systems.

Quote and Encoding Changes

Spreadsheet applications may change quote characters, alter line endings, or save in non-UTF-8 encodings—all of which violate RFC 4180 compliance and cause parsing failures.

CSV Workbench: A Free CSV File Editor That Preserves Your Data

CSV Workbench is a free CSV editor built specifically for CSV files. It uses the browser's File System Access API to read and write files directly on your local file system—no upload, no server, no data transformation.

No automatic type conversion — values are stored exactly as typed
Leading zeros preserved — ZIP codes and account numbers stay intact
No date reformatting — dates remain in their original format
RFC 4180 compliant output — saved files always use proper CSV formatting
Auto-save — changes are saved immediately to your local file
100% local processing — your data never leaves your computer

What You Can Do with the Free CSV Editor

Edit Cells Directly

Click any cell to edit its value. Changes are saved immediately to your local file via the File System Access API. No save button required.

Add and Delete Rows and Columns

Add new rows at the end of the file or insert rows at any position. Delete rows or columns that are no longer needed. All operations maintain RFC 4180 compliance.

Validate While Editing

Associate a CSV Schema with your file and validate data as you edit. The validation engine checks data types, constraints, and required fields—catching errors before they reach your systems.

Large File Support

The free CSV editor fully supports editing for files up to 50MB. For larger files, CSV Workbench provides a read-only preview of the first 200 rows while still running complete validation on the entire file.

Browser and Device Requirements

The free CSV editor requires the File System Access API, which is available in:

Chrome 86+ on laptop or desktop
Edge 86+ on laptop or desktop

Mobile devices and tablets are not supported. The CSV editor is optimized for laptop and desktop use, where CSV file editing is most commonly needed.