How it works
Add your Microsoft Excel 97–2003 file. MimiFile checks the format, converts it to Excel workbook, and provides a temporary download when the result is ready.
Upgrade an older XLS workbook to modern XLSX when a newer Excel workflow, upload portal or application expects the Office Open XML spreadsheet format.
XLS → XLSX
Drag and drop, paste a file, or browse your device.
Files are temporary and deleted automatically.
Limits: 90 MB per file · 128 MB total per batch.
Add your Microsoft Excel 97–2003 file. MimiFile checks the format, converts it to Excel workbook, and provides a temporary download when the result is ready.
XLSX modernizes the workbook container but cannot guarantee perfect migration of every legacy Excel feature. Review macros, formulas, charts, named ranges and embedded objects before replacing the XLS source.
Current source limit : 90 MB per file. Up to 10 files can be submitted in a batch, subject to the global batch ceiling.
Microsoft Excel 97–2003 is accepted here as application/vnd.ms-excel. The current source-file limit is 90 MB.
The result is produced as Excel workbook (application/vnd.openxmlformats-officedocument.spreadsheetml.sheet). Features unsupported by the destination format cannot be preserved.
Use this when a service, device or workflow accepts Excel workbook but your source file is Microsoft Excel 97–2003.
Microsoft Excel 97–2003 and Excel workbook can represent document structure differently. MimiFile imports the Microsoft Excel 97–2003 source through its isolated office-processing pipeline and writes a new Excel workbook result rather than merely renaming the extension.
Microsoft Excel 97–2003 is a workbook format that can contain cells, formulas, number formats, multiple sheets, charts and print settings.
Excel workbook is intended for editable spreadsheet workbooks. Formula syntax, charts, external links and application-specific formatting should be checked after migration.
When moving between XLS, XLSX and ODS, verify formulas, number/date formats, charts, named ranges, external links, conditional formatting and application-specific functions. The conversion is performed with an isolated headless LibreOffice profile. Features that have no equivalent in the destination format can be changed, flattened or omitted.
Check formulas, calculated values, number/date formats, sheet names, hidden sheets, charts, column widths and print settings.
The downloaded file uses Excel workbook. Check the result if the source contains transparency, animation, embedded fonts, metadata or other format-specific features.