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Expensico

XLS to XLSX Converter

Upgrade legacy Excel 97–2003 XLS files (and ODS) to modern XLSX workbooks with all sheets, values and formulas. Converted privately in your browser.

Runs in your browser. Your files are processed on your device and are never uploaded.

How to use the XLS to XLSX Converter

  1. Choose or drop your Excel 97–2003 file.
  2. Select Convert. Conversion happens instantly in your browser.
  3. Preview the result and download your Excel file.

About this Excel 97–2003 to Excel converter

Legacy .xls files are limited to 65,536 rows and are increasingly rejected by modern systems. Converting to .xlsx gives you the current Excel format with all sheets intact.

How Excel 97–2003 to Excel conversion works

  1. SheetJS reads the binary XLS (or ODS) in your browser.
  2. Sheets, cell values, formulas and number formats are written to a new XLSX workbook.

Conversion quality: High fidelity. Values, formulas, sheets and number formats are kept; some styling and macros are not.

When to convert Excel 97–2003 to Excel

  • Modernising old archives
  • Uploading to tools that only accept .xlsx

Limitations to be aware of

  • Macros (VBA), charts, pivot tables and most cell styling are not carried over.
  • Encrypted workbooks can't be read.

Excel 97–2003 vs Excel

Excel 97–2003 (XLS). XLS is the legacy binary Excel format used before 2007. Modern spreadsheet apps can still read it, but XLSX is preferred.

Excel (XLSX). XLSX is the default Microsoft Excel workbook format since Excel 2007. It can hold multiple sheets, formulas, formatting and charts.

This converter also accepts OpenDocument Spreadsheet, CSV files as input.

Frequently asked questions

Are formulas preserved?

Yes, formulas are copied along with their last calculated values.

Are my files uploaded?

No. This tool reads and processes files directly in your web browser. Nothing is sent to Expensico's servers, and the data is discarded when you close or reload the page.