How to convert CSV to Excel
- Drop one or more CSV files onto the upload area. Files ending in
.csv,.tsvor.txtare accepted. - Click Convert to Excel.
- Download the
.xlsxworkbook. Each CSV file you added becomes its own sheet in the workbook.
The conversion is done entirely in your browser. Your data is never uploaded to a server or stored, which makes the tool safe for exports from CRMs, shops and accounting systems.
Why convert CSV to XLSX?
CSV is a plain-text format: perfect for moving data between systems, but limited once a person needs to work with it. An Excel workbook (.xlsx) adds everything CSV lacks:
| Feature | CSV | XLSX |
|---|---|---|
| Multiple sheets in one file | No | Yes |
| Formulas, formatting, charts | No | Yes |
| Filters, pivot tables, frozen headers | No | Yes |
| Readable by any text editor or script | Yes | No |
| File size for large data | Larger (plain text) | Smaller (compressed) |
Opening a CSV directly in Excel also works, but it is easy to save it back as CSV by accident and lose any formatting or formulas you added. Converting to .xlsx first gives you a proper workbook from the start.
Combine several CSV files into one workbook
Because every CSV becomes a separate sheet, the tool is a quick way to bundle related exports into a single file: monthly sales reports, one CSV per store, or data from several systems that you want to compare side by side. Instead of emailing a folder of CSV files, you send one tidy Excel workbook.
If you would rather have all rows from several files in a single sheet, use Merge Excel Files with the rows appended option, which also accepts CSV files.
Tips and limitations
- Check identifiers with leading zeros. Values that look like numbers, such as postcodes, phone numbers or product codes, may be stored as numbers in Excel and lose leading zeros. Review those columns after converting.
- Dates may be interpreted differently depending on their format (
03/04/2026means different days in the US and Europe). ISO dates such as2026-04-03are the safest. - Row limit: an Excel sheet holds at most 1,048,576 rows and 16,384 columns. Larger CSV files must be split first.
- Character encoding: UTF-8 CSV files give the best results for accented and non-Latin characters.
Frequently asked questions
Can I convert several CSV files at once?
Yes. Select multiple files and they are combined into one workbook, with one sheet per CSV file.
Does the tool support semicolon or tab-separated files?
Files with the .tsv and .txt extensions are accepted along with .csv. Check the first sheet after converting to confirm the columns were split as expected.
Will the file open in Google Sheets or LibreOffice?
Yes. The .xlsx format is supported by Excel, Google Sheets, LibreOffice Calc, Apple Numbers and most other spreadsheet apps.