Skip to content
All Online Tools

XLS to XLSX

Upgrade old Excel 97–2003 workbooks to .xlsx.

Your files stay on this device

or drop them here, or paste with Ctrl+V

XLS · up to 50 files · stays on your device

How to use XLS to XLSX

  1. 1Add one or more files — drag and drop or tap to choose. Accepted: XLS.
  2. 2No settings needed.
  3. 3Press “Convert to XLSX”. Processing happens on your device.
  4. 4Download your XLSX, one by one or all together as a ZIP.

About this tool

Upgrade old Excel 97–2003 workbooks to .xlsx. Your files are processed locally in your browser, so they're never uploaded, queued or stored — which also makes it fast. It's part of our free excel & csv tools, which work together — you can pass the result straight into related tools below.

Accepts
XLS
Gives you
XLSX
Files at once
Up to 50
Processed
On your device

Frequently asked questions

Is XLS to XLSX free?

Yes. There's no sign-up, no watermark and no usage limit.

Are my files uploaded to a server?

No. XLS to XLSX runs entirely in your browser. Your files never leave your device and nothing is stored — close the tab and everything is gone.

Which file types can I use?

XLS. Files are checked by their actual content, not just the extension, so renamed or damaged files are caught early.

Is there a file size limit?

Each file can be up to 200.0 MB, and you can process up to 50 files at once. Because processing uses your device's memory, very large files work best on a computer.

Does it work on my phone?

Yes. It works in modern mobile browsers on Android and iPhone. Heavier jobs (large PDFs, OCR) are faster on a computer.