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Drop one XLSX or two hundred. Batch conversion is not a paid feature here.
Convert XLSX to XLS
A supplier portal, a bank upload form or an old internal tool accepts only Excel 97-2003 files.
SafeConvert engineFreeNo sign-upBatch supported
Waiting for files/Engine: on-device/Network requests made: 0
What actually changes
XLSX and XLS are not the same picture in two wrappers.
The workbook is written back into the old binary format, with anything the old format cannot express approximated or removed.
Worth knowing first
The row ceiling drops back to 65,536. Any data below that row is silently truncated during the conversion, and a workbook that came from a database export is very likely to exceed it without anyone noticing until a total comes out wrong.
Questions
XLSX to XLS, answered
What else gets lost?
Modern chart types, conditional formatting rules added after 2007, tables as objects, and more than three conditional formats per cell.
Is the file bigger or smaller?
Larger, usually. The binary format has no compression, where XLSX is a ZIP.
How to convert XLSX to XLS
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Choose your settings
Excel 97-2003 is lossless, so nothing is thrown away in the conversion.
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Download
Converted and deleted the moment it finishes. Never written to permanent storage.