XLS to XLSX

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Upload the legacy workbook, convert, download the XLSX.

How to Convert XLS to XLSX Online for Free

  1. Select your .xls file — or drag it into the tool.

  2. Start the conversion in your browser.

  3. Download the upgraded .xlsx.

  4. Open it in Excel or any modern spreadsheet app.

Why Use Our XLS to XLSX Converter?

Built for speed, privacy and reliability — on any device.

Modern Format, Smaller Files

XLSX’s ZIP+XML structure weighs less and resists corruption better than legacy XLS.

Everything Opens XLSX

Excel, Google Sheets, Numbers, LibreOffice and every API prefer XLSX.

Nothing Leaves Your Browser

Processed in your browser and removed right after.

Free, No Sign-Up

No account, no watermark, no limits.

Office Format Support

Supports DOCX, XLSX, PPTX and legacy formats. Formatting and layout are retained as closely as possible.

XLS to XLSX — Common Questions

XLS to XLSX Convert legacy XLS to modern XLSX — free & fast

XLS to XLSX

Convert legacy XLS to modern XLSX — free & fast

XLS to XLSX complete
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