Why upgrade XLS to XLSX?

XLSX is the modern Excel format with better compatibility, larger row/column limits, and smaller file sizes.

XLS to XLSX Converter

Upgrade legacy Excel 97-2003 .xls files to modern XLSX format.

Secure & Private

Fast Processing

No Installation Required

or drop files here

Files stay private. Automatically deleted after 2 hours.

Upload your legacy .xls file.

It is automatically converted to modern XLSX format.

Download the updated file.

Preserves Formulas

Retains Formatting

No Excel Required

Free & Secure

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