Excel to CSV Converter

About Excel to CSV Converter

Excel to CSV Converter is a free online tool that converts Excel spreadsheet files (.xlsx and .xls) into CSV (Comma-Separated Values) format. Select an Excel file, choose a sheet and delimiter, then download your CSV file—all processed locally in your browser for complete privacy.

Why convert Excel to CSV?

CSV is a universal format supported by virtually all data processing tools. Converting Excel to CSV is essential for:

- Importing data into databases (MySQL, PostgreSQL, etc.)
- Processing data with programming languages (Python, R, JavaScript)
- Using data with command-line tools and scripts
- Importing into web applications and APIs
- Sharing data across different platforms
- Reducing file size for storage or transfer
- Ensuring compatibility with older systems

CSV files are plain text, making them more portable and easier to version control than binary Excel files.

What Excel formats are supported?

This tool supports both modern and legacy Excel formats:

- .xlsx (Excel 2007 and later) - Modern XML-based format
- .xls (Excel 97-2003) - Legacy binary format

Both formats are fully supported with all features including:
- Multiple sheets
- Various data types (text, numbers, dates, formulas)
- Large spreadsheets (thousands of rows)
- Special characters and Unicode text

How do I choose which sheet to convert?

If your Excel file contains multiple sheets (worksheets), you can select which one to convert:

1. Upload your Excel file
2. The Sheet Select dropdown will populate with all available sheets
3. Choose the sheet you want to convert
4. Click 'Convert to CSV'

The tool shows the sheet name so you can easily identify the correct one. If your file has only one sheet, it will be selected automatically.

What delimiter options are available?

Choose the delimiter that best fits your needs:

- Comma (,) - Standard CSV format, most widely supported
- Semicolon (;) - Common in European locales where comma is decimal separator
- Tab (\t) - TSV format, useful for data with commas
- Pipe (|) - Alternative for data with commas and tabs
- Custom - Specify any character you need

The delimiter determines how values are separated in your CSV file. Choose based on your target application's requirements.

What about formulas in my Excel file?

The converter exports the calculated values of formulas, not the formulas themselves. For example:

- If cell A1 contains =SUM(B1:B10) with result 150
- The CSV will contain 150, not the formula

This is the standard behavior because:
- CSV format doesn't support formulas
- Most applications need the actual values, not formulas
- Values are ready to use immediately in databases or scripts

If you need to preserve formulas, consider exporting as a different format or keeping the original Excel file.

Does my data leave my device?

No. All Excel to CSV conversion happens entirely in your browser using JavaScript. Your file:

- Never uploads to any server
- Never leaves your computer
- Is processed completely client-side
- Remains private and secure

You can verify this by:
- Disconnecting from internet after page loads (tool still works)
- Checking browser network tab (no file uploads)

This makes the tool safe for sensitive data like financial records, customer information, or confidential business data.

What's the difference between UTF-8 and UTF-8 with BOM?

Both are Unicode encodings that support international characters:

UTF-8 (Recommended):
- Standard encoding for most applications
- Compatible with modern tools and programming languages
- Smaller file size
- Best for: APIs, databases, programming

UTF-8 with BOM:
- Includes a Byte Order Mark at the start of file
- Helps Excel and some Windows tools recognize UTF-8 encoding
- Slightly larger file size
- Best for: Opening in Excel, Windows Notepad, legacy applications

If your CSV will be opened in Microsoft Excel, UTF-8 with BOM ensures proper display of special characters (é, ñ, 中, etc.). For most other uses, standard UTF-8 is preferred.

Should I use CRLF or LF line endings (RFC 4180)?

The CSV standard RFC 4180 mandates CRLF (\r\n) as the row terminator, and Microsoft Excel on Windows expects it too. This tool defaults to CRLF so your file round-trips cleanly into Excel and strict parsers.

Use the Line Endings dropdown to choose:

- CRLF (Windows / Excel / RFC 4180) - the safe default. Required for PostgreSQL COPY, SQL Server BULK INSERT, and most database loaders.
- LF (Unix / macOS) - choose this for awk/cut/sed pipelines, Git-friendly diffs, or Linux/macOS tooling that expects newline-only files.

The tool also fully escapes any cell that contains a carriage return, line feed, the delimiter, or a double-quote by wrapping it in quotes, so multi-line cells never break your row boundaries.

How are numbers and dates handled (serial dates, leading zeros, scientific notation)?

The converter exports the value as Excel stores it, which is the #1 thing to watch for professionals:

- Dates: Excel may keep dates as serial numbers (e.g. 45000) rather than formatted text. If a date column exports as numbers, format that column as Text or a date string in Excel before converting.
- Leading zeros: ZIP codes, phone numbers and product codes like 00123 lose their leading zeros if Excel stored them as numbers. Format the cells as Text in Excel first to preserve them.
- Scientific notation: long numeric IDs (e.g. 1.23457E+14) get stored in scientific form by Excel; convert the column to Text to keep the full digits.

CSV is plain text with no number formatting, so the fidelity is determined by how Excel holds the value. Formatting the source cells as Text is the reliable fix.

Which delimiter should I use for European/decimal-comma locales?

In many European, Latin American, French and Portuguese locales the comma is the decimal separator (e.g. 1,5 means one-and-a-half). Using a comma delimiter there collides with the decimals and corrupts columns.

Choose the Semicolon (;) delimiter for those locales - it is what Excel itself uses when 'comma' is the regional decimal symbol, so the file opens correctly with a double-click.

Tab is a good choice for data that contains both commas and semicolons. If you also need the file to open in Excel by double-click, add a sep= hint line (e.g. sep=; on the first line) so Excel auto-detects the delimiter, then convert back to .xlsx via Data > From Text/CSV to round-trip into a workbook.

Can I convert large Excel files?

Yes, this tool can handle large Excel files, but performance depends on your device:

Typical performance:
- Small files (< 1 MB, few thousand rows): Instant
- Medium files (1-10 MB, tens of thousands rows): A few seconds
- Large files (10-50 MB, hundreds of thousands rows): 10-30 seconds
- Very large files (> 50 MB): May take longer or require more memory

Tips for large files:
- Close other browser tabs to free memory
- Use a modern browser (Chrome, Firefox, Edge)
- If conversion fails, try splitting the Excel file into smaller sheets
- Consider using desktop tools for files over 100 MB

The tool processes everything in browser memory, so available RAM is the main limitation.