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.

How to XLS to XLSX Converter

Upload your legacy .xls file.

It is automatically converted to modern XLSX format.

Download the updated file.

Features

Preserves Formulas

Retains Formatting

No Excel Required

Free & Secure

When to use XLS to XLSX Converter

XLS to XLSX Converter helps analysts, operations teams, developers, and finance teams. Use it when you need to turn XLS files into XLSX output, prepare a cleaner sharing copy, or finish a document workflow without installing desktop software.

convert structured data into spreadsheets or documents
make machine data readable
prepare data files for reporting

Quality checklist

Validate row counts, delimiters, dates, and encodings.
Check nested fields after conversion.
Avoid sharing sensitive data without review.

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Security

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XLS to XLSX Converter

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

Frequently Asked Questions

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