Convert XLS to XLSX
or click to upload
XLS / ODS / XLSM
Update old Excel 97-2003 files to the modern XLSX format. All sheets and cell values come along, and the conversion runs in your browser without uploading anything.
- No watermarks
- Fast results
- 100 % in-browser
- Zero sign-up
How It Works
Use XLS to XLSX in three quick steps.
Upload your XLS file
Drag and drop one or more spreadsheets or browse your device.
Convert to XLSX
Your browser re-saves each workbook in the modern format.
Download the XLSX file
Save the workbook, or a ZIP when you converted several files.
What is an XLS to XLSX converter?
XLS is the legacy Excel format used up to 2003. Modern tools, online platforms and data pipelines expect XLSX, which is smaller, supports far more rows and is easier for software to read. An XLS to XLSX converter re-saves the workbook in the modern format.
For files that rely on charts or macros, open them in Excel and use Save As instead.
All sheets kept
Every worksheet in the workbook is converted, including hidden ones.
Values and formulas
Cell contents, number formats and formulas are carried over.
Also reads ODS and XLSM
OpenDocument spreadsheets and macro-enabled workbooks can be saved as plain XLSX as well.
Advanced formatting may be simplified
Charts, images, macros and some styling are not preserved by this converter.
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Why Use Our XLS to XLSX Tool
Fast, free and simple, with nothing to install.
Fast Results
Convert XLS to XLSX in seconds. It is processed on your device, so there is no upload wait.
Private by Design
Your files never leave your browser. Nothing is uploaded to a server and nothing is stored.
Works Everywhere
Use it on desktop, tablet or phone. There is no software to install and no extension needed.
Completely Free
No account, no watermark and no limit on how many files you process.
Frequently Asked Questions
Common questions about XLS to XLSX.
Upload the .xls file, press Convert to XLSX and download the new workbook.
Yes. All sheets, cell values and formulas are carried over.
They are not preserved by this converter. Use Excel's Save As if you need them.
XLS, XLSX, XLSM and ODS files can all be saved as XLSX.
No. It is converted locally in your browser.