Data & spreadsheets converter
Convert XLS to XLSX online for free
Drop your file here
or choose a file from your device
Input: XLS · Output: XLSX
Convert a legacy XLS spreadsheet to the modern XLSX format for compatibility with current Excel, Google Sheets and other applications that no longer support the older binary format.
About this XLS to XLSX conversion
What to select
Select an XLS file to produce a compatible XLSX locally. Formulas and basic formatting are preserved where supported.
What you receive
Table data is exported as XLSX for download without sending the source file to a server.
Private processing
ConvertME runs this conversion in the browser on your device. Selected files are not transferred to a processing server, and downloads are created locally after conversion.
Format details
- Input
- XLS
- Output
- XLSX
- Processing
- In browser
- Cost
- Free
When to use this converter
Use this page when you need a focused XLS to XLSX conversion without installing desktop software or sending the source file to a remote conversion queue.
Practical use cases
- Convert a legacy XLS spreadsheet to the modern XLSX format for compatibility with current Excel, Google Sheets and other applications that no longer support the older binary format.
- Select an XLS file to produce a compatible XLSX locally. Formulas and basic formatting are preserved where supported.
- Table data is exported as XLSX for download without sending the source file to a server.
Best practices before downloading
- Start from the cleanest available XLS file because conversion cannot recover missing detail or corrupted data.
- Open the downloaded XLSX file before deleting the original, especially for professional or archival work.
- Use a current browser and avoid closing the tab while the local conversion engine is running.
Common issues to check
- Password-protected, corrupted or unusually large XLS files may fail in the browser.
- Metadata, embedded scripts, advanced styling or hidden document features may not be preserved in the XLSX output.
- Review the result before using it in legal, medical, financial, regulatory or production workflows.
XLS vs XLSX: what changes
The converter changes the container or export format. It does not claim to improve the source file beyond what the browser can read and render.
- Source format
- XLS — Legacy Excel 97–2003 binary format (.xls)
- Download format
- XLSX — Modern OpenXML spreadsheet (.xlsx), current Excel standard
- Conversion type
- Legacy format → Modern Excel format
- Size impact
- XLSX output size is similar to XLS but in open, XML-based format
- Privacy model
- Browser-based local processing with no file upload to ConvertME.
Related searches this page answers
How it works
Convert XLS in three steps
Choose a converter
Pick the exact input and output format you need.
Drop your file
Select a local file. Nothing is uploaded to our servers.
Download the result
Conversion finishes in your browser and exports locally.
FAQ
XLS to XLSX questions
How do I convert XLS to XLSX?
Choose a XLS file, select Convert now and download the resulting XLSX file. Processing happens in your browser.
Is this XLS to XLSX converter private?
Yes. Your selected file is processed locally and is not uploaded to ConvertME.
Do I need an account to convert XLS files?
No. The converter is free to use without sign-up or watermarks.
What will my XLSX download contain?
Table data is exported as XLSX for download without sending the source file to a server.