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Convert Excel (XLS/XLSX) to CSV

Convert Excel spreadsheets (.xls/.xlsx) to CSV directly in your browser. Pick a sheet, choose a delimiter, and export. No upload required.

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Drop your file hereor click to browseSupports Excel files (.xlsx, .xls, .ods) (Max 100MB)

**Excel to CSV conversion** is the process of transforming Microsoft Excel spreadsheets (.xls and .xlsx) into Comma-Separated Values files, a plain-text format defined by RFC 4180 that every programming language, database, and operating system can parse natively. Excel files store data in binary formats (BIFF for .xls, Office Open XML for .xlsx) that require specialized software to read, while CSV is universally accessible. When you export an Excel file to CSV, the workbook's active sheet is flattened into a simple text file where each row becomes a line and each cell value is separated by a comma. This converter reads your Excel file entirely in your browser using the SheetJS library, which supports both the legacy .xls (BIFF) format and the modern .xlsx (Office Open XML) format. You can select which worksheet to convert, choose a custom delimiter (comma, semicolon, tab, or pipe), and toggle whether the first row should be treated as a header. Because all parsing happens client-side, your spreadsheet data never leaves your device. The tool handles files up to 100 MB and preserves data types accurately, including dates, numbers, and boolean values, without the formatting corruption that often occurs when Excel auto-converts data.

How to use the Convert Excel to CSV tool

  1. Upload your Excel file: Drag and drop your .xls, .xlsx, or .ods file, or choose a file from your file explorer.
  2. Select a sheet: Pick the specific worksheet you want to convert from the dropdown menu.
  3. Configure output settings: Choose a CSV delimiter (comma, semicolon, tab, or pipe) and toggle whether the first row is a header.
  4. Convert to CSV: Click the "Convert Data" button to parse the selected sheet into CSV format.
  5. Export results: Copy the CSV output to your clipboard or download it as a file.

Frequently asked questions

Does this Excel to CSV converter preserve leading zeros in numbers?
Yes. Unlike opening a CSV in Excel (which strips leading zeros from values like zip codes), this converter reads the raw cell values directly from the binary spreadsheet format using SheetJS. Leading zeros, date formats, and number precision are preserved exactly as they appear in the original Excel file, following the data integrity principles outlined in the W3C CSV on the Web specification.
Can I convert a specific worksheet from a multi-sheet Excel file?
Yes. After loading your .xls or .xlsx file, the tool displays a dropdown menu listing every worksheet in the workbook. Select the sheet you want to convert, and only that sheet will be exported to CSV format. SheetJS parses both the legacy .xls (BIFF) format and the modern .xlsx (Office Open XML) format as documented in the Microsoft Office Open XML specification.
What delimiters can I use for the CSV output?
You can choose from comma (default), semicolon, tab, or pipe as the output delimiter. The semicolon option is useful for European locales where commas are used as decimal separators. All delimiter options produce RFC 4180 compliant output, as specified in IETF RFC 4180 "Common Format and MIME Type for CSV Files."
How does this tool handle large Excel files with thousands of rows?
The converter uses SheetJS streaming mode to process files in chunks, keeping memory usage stable even for spreadsheets with hundreds of thousands of rows. The Web Worker architecture ensures the browser interface stays responsive throughout the conversion, following modern web performance best practices documented by the Web Performance Working Group.
Is the converted CSV compatible with databases and programming languages?
Yes. The output follows RFC 4180 format with proper quoting and escaping, making it compatible with MySQL, PostgreSQL, SQLite, Python pandas, R, and any tool that reads standard CSV files. The CSV format is universally supported across all major programming languages and database systems.

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