Tools / File Converter / XLS to XLSX Converter

XLS to XLSX Converter

Convert XLS files to XLSX. Free and without uploading.

This tool converts XLS files to XLSX. XLS is the old binary format of Excel 97–2003; older software and some institutions still require it.

XLSX is Microsoft Excel’s current workbook format. It holds multiple sheets, formatting and formulas. All sheets, numbers and dates are carried over. Some formatting, such as cell colours, may be lost in the target format.

Conversion happens inside your browser; your files are never sent to a server.

How to use

1. Drag and drop your XLS files, paste them, fetch one from a link, or use "Choose files".
2. The target format is preselected; you can add several files at once.
3. Press "Convert" and download the XLSX files.

Frequently asked questions

Is anything lost when converting XLS to XLSX?

The content is kept; formatting the target format doesn’t support (such as colours or fonts) may be lost.

How many files can I convert at once?

There is no limit. Download the results one by one or as a ZIP.

Are my files uploaded?

No. Your XLS files are converted to XLSX inside your browser.