Excel (XLSX) to CSV Converter
Handles Up to 1 Million Rows

Convert Excel XLSX files to clean CSV format instantly in your browser. Dates are preserved as ISO 8601, numbers stay accurate.

Drag & drop your file here, or browse

Accepts: .xlsx (up to 200 MB)

Your data stays in your browser. By using this tool, you agree to our Terms and Privacy Policy.

How to Convert Excel (XLSX) to CSV

Drag and drop your XLSX file onto the drop zone at the top of the page, or click to browse and select a file.

Conversion starts automatically. Dates and numbers are detected and preserved in the CSV output.

Click the "Download CSV" button to save the converted result.

Key Features of This XLSX to CSV Converter

100% Local Processing: Your files are never uploaded to a server. All conversion happens in your browser, so your sensitive data stays private.
Smart Date Detection: Excel date cells are automatically detected and converted to ISO 8601 format (YYYY-MM-DD). Built-in and custom date formats are recognized.
Free with No Limits: No row limits, no file count restrictions, and no account required. Start converting right away.

Excel (XLSX) vs CSV: What's the Difference?

Excel (XLSX) stores data in a rich binary format with formatting, formulas, and multiple sheets. CSV is a simple plain-text format that works everywhere.

	Excel (XLSX)	CSV
Structure	Multiple sheets, rich formatting	Single flat table
Data types	Numbers, dates, booleans, text	Everything is a string
Compatibility	Excel, Google Sheets, LibreOffice	Universal
File size	Larger (ZIP-compressed XML)	Compact
Version control	Binary diffs only	Line-by-line diffs

Benefits of Converting XLSX to CSV

Universal Compatibility — CSV files can be opened by any text editor, database, programming language, or spreadsheet application
Data Pipeline Integration — Most ETL tools, databases (PostgreSQL, MySQL), and data science frameworks (pandas, R) import CSV natively
Version Control Friendly — CSV files produce meaningful line-by-line diffs in Git, making data changes trackable

Frequently Asked Questions

Is my data uploaded to a server?

No. Your file never leaves your browser. All processing happens locally using WebAssembly. No data is sent to any server.

Can I convert large Excel files to CSV?

Yes. This tool uses an efficient SAX parser to process XLSX files without loading the entire document into memory. Files up to 200MB are supported.

Are dates preserved in the CSV output?

Yes. Excel date cells are detected and converted to ISO 8601 format (YYYY-MM-DD or YYYY-MM-DD HH:MM:SS) in the CSV output. Both built-in and custom Excel date formats are recognized.

Which sheet is converted?

The first sheet in the workbook is converted. Multi-sheet conversion is not currently supported.

What is the file size limit?

The input limit is 200MB. XLSX files are compressed, so the actual data processed may be larger than the file size.

Does the tool handle formulas?

Yes. The cached (evaluated) value of each formula cell is used in the CSV output. The formula text itself is not included.