ConvertWhat happens when you convert CSV to XLSX
- The separator (comma, semicolon, tab or pipe) and the text encoding are detected automatically.
- Numbers become real numbers you can calculate with, while values like 00123 or long IDs stay text.
CSV vs XLSX
| Feature | CSV | XLSX |
|---|---|---|
| Multiple sheets | No | Yes |
| Formulas | No | Yes |
| Numbers & dates | No | Yes |
| Nested data | No | No |
| Best for | Imports, exports, databases | Spreadsheets with several sheets |
How to convert CSV to XLSX
- Drop your CSV files on the box above, or click it to choose files. You can add many at once.
- Adjust the options if you want. The defaults work well for most files.
- Click Download for each XLSX file, or "Download all" to get a ZIP.
Frequently asked questions
Is it safe to convert my files here?
Yes. Conversion happens entirely in your browser. Your files are never uploaded to a server, so nobody else can see them.
Is it free? Are there limits?
It's completely free, with no sign-up, watermarks or daily limits. The only limit is your device's memory for very large files.
Can I convert many CSV files at once?
Yes. Drop as many files as you like; they're converted one after another and you can download them all as a ZIP.
Will leading zeros and long numbers be kept?
Yes. Values like 00123, phone numbers and IDs longer than 15 digits stay as text, while ordinary numbers become real numbers.