CSV to Excel Converter

About CSV to Excel Converter

CSV to Excel Converter is a free online tool that converts CSV (Comma-Separated Values) files into Excel spreadsheet format (.xlsx). Upload a CSV file or paste CSV data, customize your options, and download the converted Excel file—all processed locally in your browser for complete privacy.

Why convert CSV to Excel?

Converting CSV to Excel offers several advantages:

- Better formatting: Excel supports colors, fonts, borders, and styling
- Multiple sheets: Combine multiple CSV files into one workbook
- Formulas: Add calculations and formulas after conversion
- Data validation: Use dropdowns, date pickers, and input restrictions
- Charts and graphs: Visualize your data with Excel's charting tools
- Cell formatting: Apply number formats, currency, percentages, dates
- Easier editing: Excel's interface is more user-friendly than text editors
- Professional presentation: Create polished reports and documents

While CSV is great for data transfer, Excel provides richer features for data analysis and presentation.

What CSV formats are supported?

This tool supports various CSV formats and delimiters:

- Standard CSV (comma-separated)
- European CSV (semicolon-separated, common where comma is decimal separator)
- TSV (tab-separated values)
- PSV (pipe-separated values)
- Custom delimiters (any character you specify)
- Auto-detection (tool identifies the delimiter automatically)

The converter handles:
- Quoted fields with delimiters inside
- Multi-line fields (text spanning multiple rows)
- Mixed data types (text, numbers, dates)
- Special characters and Unicode text
- Large files with thousands of rows

Can I customize the sheet name?

Yes! By default, the tool creates a sheet named "Sheet1", but you can customize it:

1. Enter your desired sheet name in the "Sheet Name" field
2. Use descriptive names like "Sales_Data" or "Customer_List"
3. Avoid special characters that Excel doesn't allow (:, ?, *, [, ], /, \)
4. Keep names under 31 characters (Excel's limit)

Custom sheet names make your Excel file more organized and professional, especially when you plan to add more sheets later.

Does the tool preserve data types?

Yes, the converter attempts to preserve data types intelligently:

- Numbers: Recognized and formatted as numeric values
- Dates: Common date formats are detected and converted to Excel dates
- Text: Strings are preserved as text
- Booleans: true/false values are maintained
- Empty cells: Blank values remain empty

However, if Excel misinterprets a value (like ZIP codes losing leading zeros), you may need to format columns after conversion. The converter outputs standard Excel format that you can further refine in Excel.

What about large CSV files?

The tool can handle reasonably large CSV files, with performance depending 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

Excel limitations:
- Maximum 1,048,576 rows per sheet
- Maximum 16,384 columns per sheet

For extremely large datasets:
- Consider splitting into multiple sheets
- Use database tools for datasets exceeding Excel's limits
- Close other browser tabs to free memory during conversion

Is my data secure and private?

Absolutely. Your data is completely secure:

- All conversion happens in your browser (client-side)
- No data is uploaded to any server
- No data is stored, logged, or transmitted
- Works offline after page loads
- No cookies or tracking for your CSV data

You can verify privacy by:
- Checking browser network tab (no file uploads)
- Disconnecting internet after page loads (tool still works)
- Reviewing the open-source code

This makes the tool safe for sensitive data like:
- Financial records
- Customer information
- Confidential business data
- Personal information (PII)
- Internal reports and analytics

What's the output format?

The tool outputs modern Excel format:

- File extension: .xlsx
- Excel version: Compatible with Excel 2007 and later
- Compatible with:
- Microsoft Excel (Windows, Mac)
- Google Sheets (upload the .xlsx file)
- LibreOffice Calc
- Apple Numbers
- OpenOffice Calc
- Online Excel (Office 365)

The .xlsx format is XML-based, open standard, and widely supported. It's smaller than legacy .xls format and supports modern Excel features.

After download, you can open the file in any compatible spreadsheet application and add formulas, formatting, charts, or additional sheets as needed.

Can I convert multiple CSV files at once?

Currently, this tool converts one CSV file at a time. However, you can:

Workflow for multiple files:
1. Convert each CSV file separately
2. Download each as an Excel file
3. Open the Excel files and copy sheets between workbooks
4. Or use Excel's "Move or Copy Sheet" feature to consolidate

For automated batch conversion of many files:
- Consider using desktop tools like Microsoft Power Query
- Use programming scripts (Python with pandas, openpyxl)
- Use command-line tools for bulk operations

For occasional conversions, this browser tool is quick and convenient. For regular bulk conversions, desktop automation may be more efficient.