Excel to CSV Converter — Convert XLSX & XLS to CSV Online
Fast, secure in-browser Excel to CSV converter with multi-sheet support, custom delimiters, and zero file uploads.
- Runs in your browser
- Free, no signup
Drop your Excel spreadsheet here
or
Fast, 100% private in-browser conversion. Max file size: 50 MB. Files are never uploaded to any server.
Worksheets in Workbook
All spreadsheet conversions run 100% locally in your browser. Your spreadsheets, numbers, and tabular data are never uploaded to any server.
Microsoft Excel workbooks (.xlsx and .xls) are widely used for financial reporting and planning, but automated data pipelines, databases, and programming scripts require plain-text CSV or TSV formats.
This online converter transforms Excel files into clean, RFC 4180 compliant CSV files directly in your web browser. It supports multi-sheet workbooks with individual sheet selection or full-workbook ZIP export, preserves Unicode characters and leading zeros, evaluates formula results safely, and never uploads your private spreadsheets to an external server.
How to use this tool
- Drag and drop your Excel file (.xlsx, .xls, .ods, or .xlsb) into the upload box, or click Browse to select from your computer.
- Choose which worksheet you wish to convert using the sheet tabs.
- Optionally customize your delimiter (comma, semicolon, tab, pipe), line endings (CRLF, LF), or character encoding (UTF-8, UTF-8 with BOM).
- Preview the resulting table grid or raw CSV text, then click "Download CSV" or "Download All Sheets (ZIP)".
Data Integrity and CSV Format Limitations
CSV is a lightweight, plain-text format that stores raw tabular records separated by delimiters. Because CSV contains no styling or execution layer, it cannot preserve cell background colors, custom fonts, chart widgets, images, merged cells, or macro scripts.
Formula cells are exported as their last evaluated/cached display values. Formulas are never executed during conversion, ensuring strict protection against macro malware or malicious spreadsheet links.
Converting Multi-Tab Workbooks into ZIP Archives
Standard CSV files can only represent a single tabular grid. When your Excel workbook contains multiple sheets (e.g., monthly sales tabs or departmental summaries), ToolDuck allows you to preview and download each sheet individually, or download all sheets at once packaged inside a clean ZIP archive.
Frequently asked questions
Which Excel formats are supported?
You can convert modern Office Open XML spreadsheets (.xlsx), legacy binary Excel workbooks (.xls), OpenDocument spreadsheets (.ods), and Excel binary workbooks (.xlsb).
Why should I use UTF-8 with BOM?
If your spreadsheet contains non-English characters, accented letters, or currency symbols (such as ₹, €, or £), saving with a Byte Order Mark (UTF-8 with BOM) ensures Microsoft Excel displays characters correctly when opening the CSV file.
Are my confidential spreadsheets uploaded to ToolDuck servers?
Never. All parsing, sheet extraction, and CSV generation occur 100% client-side in your browser using JavaScript. No files, rows, or numbers leave your computer.
What is the maximum file size limit?
You can upload workbooks up to 50 MB in size. Large sheets with tens of thousands of rows convert smoothly within seconds.