Free XLS to Excel (XLSX) converter

Why convert XLS to XLSX?

People convert XLS to XLSX because XLS is Excel’s pre-2007 format, and current tools treat it as legacy baggage, while XLSX gives you real cells, number formats and multiple sheets in Excel.

How to convert XLS to XLSX

1. Choose your XLS file. Drop it on the box above, or tap to browse. You can pick several files at once.
2. Confirm the target is .xlsx. It is preselected when your browser can encode it; otherwise the closest available target is chosen. Adjust quality, size or the other options if you want to.
3. Convert and download. Press Convert, then Download. Your file stays on your device the whole time.

What is a .xls file?

XLS is the old binary Excel format, used from 1997 to 2003 and still produced by plenty of legacy systems and bank exports. Excel still opens one, but it caps out at 65,536 rows, which modern data regularly exceeds.

What is a .xlsx file?

XLSX is the modern Excel workbook: multiple sheets, cell formatting, formulas and dates that know they are dates. It is what most people mean by “a spreadsheet”, and like DOCX it is really a ZIP of XML underneath.

What to expect from this conversion

Cell values are carried across exactly as they appear. Formulas become their calculated results, and formats that hold only one table — CSV and TSV — take the first sheet of a multi-sheet workbook. Only cell values cross over, not formulas or macros.

Is it private?

Yes, by design. Every conversion happens inside your own browser using your device’s processor — there is no server that receives your XLS file, so there is nothing for anyone to store, scan or leak. You can confirm it yourself: open your browser’s developer tools, watch the Network tab while you convert, and you will see no upload.

Questions about XLS to XLSX

Is this XLS to Excel converter free?

Yes, completely. There is no account, no daily limit, no watermark and no premium tier.

Is my XLS file uploaded to a server?

No. The conversion runs inside your own browser using your device's processor. The file is read from your disk, converted in memory and saved back to your disk — nothing is transmitted, so there is nothing for anyone to store.

Can I convert XLS to Excel online without downloading software?

Yes. This is an online XLS to Excel converter that runs in your browser, so there is nothing to install and no app to trust with your files. It works the same on a phone.

What happens to the quality?

Cell values are carried across exactly as they appear. Formulas become their calculated results, and formats that hold only one table — CSV and TSV — take the first sheet of a multi-sheet workbook. Only cell values cross over, not formulas or macros.

Can I convert several XLS files at once?

Yes. Select as many files as you like and they are converted one after another in a single tap, with a download for each and a zip of all of them.

Should I keep the original XLS file?

Yes — keep it, converting never touches it. The reason to make a copy in another format is that XLS is Excel’s pre-2007 format, and current tools treat it as legacy baggage.

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