Data

XLSX test files, any size.

Set a size and generate a structurally valid XLSX immediately. Nothing is uploaded and nothing is stored.

0bytes
Exact size

XLSX, built to spec.

Each file is a workbook with one sheet, readable by Excel and openpyxl. The size you ask for is reached with a binary part inside the package, outside the sheet data, so the result opens in Microsoft Excel, LibreOffice Calc, Numbers and openpyxl. Most people generate these for testing spreadsheet imports and bulk-upload endpoints.

Questions.

How small can an XLSX file be?

About 2,439 bytes. Below that the format cannot carry its mandatory structure, let alone padding.

Will the file open normally?

Yes — it opens in Microsoft Excel, LibreOffice Calc, Numbers and openpyxl, because the padding lives in a binary part inside the package, outside the sheet data.

Can I ask for an unusual size?

Any byte count above the minimum works, including values like 3,145,728 or 27.5 MB. Drag the caliper or type the number.

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