Upload .xlsx or .xls file
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How to Convert Excel to CSV
- Select the Excel → CSV tab.
- Upload your .xlsx or .xls file.
- If the file has multiple sheets, select which sheet to export.
- Preview the data in the table to confirm it looks correct.
- Click Download CSV to save the file.
How to Convert CSV to Excel
- Select the CSV → Excel tab.
- Upload your .csv file or paste the CSV data directly.
- Preview the data to verify the columns and rows are parsed correctly.
- Click Download Excel to save as .xlsx.
Excel vs. CSV — Key Differences
Understanding the difference helps you choose the right format for your use case:
- CSV (Comma-Separated Values): A plain text format that stores tabular data using commas to separate fields. Universally compatible with any database, programming language, or application that handles data. No formatting or formulas.
- Excel (.xlsx): A binary spreadsheet format that supports multiple sheets, formulas, formatting, charts, and more. Required for Microsoft Excel and compatible applications. Not directly readable by most databases.
Use CSV for data interchange with databases, APIs, and programming. Use Excel when you need formatting, formulas, or multiple sheets.
When to Use Each Format
- Export from a database → CSV: SQL databases and data warehouses export to CSV natively.
- Import into Google Sheets → CSV or Excel: Both are supported; CSV is simpler.
- Share with non-technical users → Excel: Most business users have Excel or can open .xlsx.
- Machine-readable data → CSV: Python, Node.js, Ruby, and most languages parse CSV easily.
- Preserve multiple sheets → Excel: CSV can only hold one sheet. Use Excel if multiple tabs matter.
Frequently Asked Questions
Does it support .xls (old Excel format)?
Yes. Both .xlsx (Excel 2007+) and legacy .xls (Excel 97–2003) files are supported using the SheetJS library.
What happens to multiple sheets?
When converting Excel to CSV, you can choose which sheet to export. Each sheet exports as a separate CSV file. When converting CSV to Excel, the data is placed in the first sheet of the new workbook.
Are formulas preserved?
Formulas are not preserved in CSV export — only the computed values are saved. Excel to Excel conversions preserve formulas.
Is my data uploaded to a server?
No. All conversion happens in your browser using SheetJS. Your spreadsheet data never leaves your device.