Convert Excel XLSX to CSV, Free and Private

Convert an Excel .xlsx spreadsheet into plain CSV, in your browser — strips formatting down to raw data.

Universal File Converter: Private & Fast

Convert images, videos, audio, and documents directly in your browser. Your files never leave your device, ensuring 100% privacy and security.

Data & Docs Converter

Convert CSV to JSON, or Markdown to HTML completely offline.

Mock Data Generator•JSON Formatter

Drop your file here, or browse

Maximum file size: 50 MB

Supported: CSV, JSON, YAML, XML, TXT, B64, MD, DOCX, XLSX, EPUB

Output format

100% In-Browser Processing

Your files are processed strictly in local device memory. Nothing is uploaded — see how, and check for yourself.

How It Works

How to convert files with DuckConvert

Select Your File

Choose the file you want to convert from your device or drag and drop it into the converter.

Choose Output Format

Select your desired output format and any specific settings for your conversion.

Convert & Download

Click "Start Conversion" and wait for the local process to finish, then download your new file.

Don't take our word for it

This conversion runs entirely in your browser — nothing is uploaded. See exactly how, and check for yourself using your browser's DevTools Network tab.

How It Works

Conversion Mechanics

CSV is the lowest-common-denominator format for spreadsheet data — every database import tool, script, and legacy system accepts it, while plenty choke on the .xlsx binary format's formatting, formulas, and multiple sheets. This pulls the data out as plain comma-separated values, ready for a database import or a script.

Why It's Private

Runs Entirely In Your Browser: Files are decoded and re-encoded strictly in local memory.
No Network Requests: The converter makes no calls to any server — check your browser's DevTools Network tab to confirm.
Nothing to Sign Up For: No account, no upload, and no server-side storage of your files.
Runs On Your Hardware: Processing uses your own device's CPU via Web Workers, not a remote server.

Step-by-Step XLSX to CSV Local Guide

Select File

Drop your .xlsx file into the box above.

Configure

Confirm CSV is selected as the output format.

Convert

Click Convert — the spreadsheet is parsed locally in your browser.

Save Result

Download the resulting .csv file.

Frequently Asked Questions on Secure XLSX to CSV Conversion

The first (active) sheet is exported. If you need other sheets, open the file and export the relevant sheet as XLSX first.

No — formulas are exported as their last calculated value, since CSV has no concept of formulas.

No — CSV is plain text only, so all formatting, colors, and fonts are dropped, leaving just the raw values.