About the CSV to Excel Online Free Tool

The CSV to Excel Online Free Tool turns a plain comma-separated file into a real .xlsx workbook, so you can sort, filter, format, and add formulas.

Conversion runs on the IO Tools server using LibreOffice, the same engine behind most open-source document pipelines. Uploaded files are converted and deleted immediately; they are never stored or shared.

Opening a CSV directly in Excel works, but the file stays a CSV: it cannot hold formatting, multiple sheets, or formulas, and Excel nags you every time you save. Converting once gives you a genuine workbook.

This tool has no in-browser mode. A browser has no office engine of its own, so if the server is unavailable the tool says so plainly rather than producing a poor imitation.

How to Use CSV to Excel Online

1. Choose a .csv file.
2. Convert it to XLSX.
3. Download the workbook.

How the Data Is Read

Types are detected from the values:
- Numbers and dates become real numbers and dates rather than text, so sorting and arithmetic work.
- Quoted fields containing commas or line breaks are handled correctly.
- A leading row of headers stays as the first row; add a filter in Excel once converted.

Common Use Cases

• Turning a database or analytics export into a workbook you can actually format.
• Preparing a CSV for someone who needs to work in Excel rather than a text editor.
• Getting rid of the repeated "keep this format?" prompt when saving a CSV in Excel.

Quick FAQ

Will my original file be changed?
No. The XLSX is generated as a separate file.

Are files uploaded?
Yes. Building a real workbook needs a spreadsheet engine a browser does not have, so the file is sent to the IO Tools server, converted with LibreOffice, returned, and deleted immediately.

What about semicolon-separated files?
They are detected and handled. Many European locales export CSV with semicolons, and the converter reads the separator from the file.

Will long numbers keep their leading zeros?
Values that look numeric become numbers, so leading zeros are dropped, exactly as they would be opening the CSV in Excel. Quote such fields in the source if they are codes rather than numbers.