Are my XLS files uploaded anywhere?

Yes — this conversion needs software that cannot run in a browser, so the file is uploaded over an encrypted connection. It is deleted as soon as the job finishes, and the result is removed after 60 minutes.

Is converting XLS to XLSX free?

The free plan covers three server conversions a day, for files up to 25 MB. There is no watermark on the result.

Does converting XLS to XLSX lose quality?

XLS and XLSX describe content in fundamentally different ways, so the conversion is a reconstruction rather than a copy. The result is faithful, but not byte-for-byte equivalent. Formatting survives; macros, embedded objects and revision history usually do not.

Do I need to install anything to open XLSX files?

No. The conversion runs on our side and gives you a finished XLSX file; opening it needs whatever software normally handles Excel Workbook.

XLStoXLSX

Convert XLS to XLSX

Up to 3 files at once, 100 with Pro. Mixed formats are fine.

You can convert XLS to XLSX free and without an account: drop the file above and the XLSX is ready to download in a second or two. The file is sent over an encrypted connection, converted on our server and deleted as soon as the job finishes.

What XLS and XLSX are for

The old binary Excel format, capped at 65,536 rows.

The Excel format since 2007. Several sheets, formulas, formatting.

How to convert XLS to XLSX

Drop your XLS file onto this page, or click to pick one.
Choose XLSX as the target and start the conversion.
Download the finished XLSX file.

XLS vs XLSX: what changes

XLS compared with XLSX
	XLS	XLSX
Full name	Excel 97-2003 Workbook	Excel Workbook
File extension	.xls	.xlsx
Media type	application/vnd.ms-excel	application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

Quality: The result is a close reconstruction rather than an exact copy. Check it before relying on it.
Where it runs: This conversion runs on our server, because it needs software a browser cannot run.
What can be lost: Formatting survives; macros, embedded objects and revision history usually do not.

XLS to XLSX: common questions

Are my XLS files uploaded anywhere?: Yes — this conversion needs software that cannot run in a browser, so the file is uploaded over an encrypted connection. It is deleted as soon as the job finishes, and the result is removed after 60 minutes.
Is converting XLS to XLSX free?: The free plan covers three server conversions a day, for files up to 25 MB. There is no watermark on the result.
Does converting XLS to XLSX lose quality?: XLS and XLSX describe content in fundamentally different ways, so the conversion is a reconstruction rather than a copy. The result is faithful, but not byte-for-byte equivalent. Formatting survives; macros, embedded objects and revision history usually do not.
Do I need to install anything to open XLSX files?: No. The conversion runs on our side and gives you a finished XLSX file; opening it needs whatever software normally handles Excel Workbook.