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How-To Guide

How to Convert XLS to XLSX

XLS is Excel's binary format from the pre-2007 era. Modern Excel still opens XLS files, but XLSX is the current standard — it's faster to load, supports more rows (1,048,576 vs 65,536), allows richer formatting, and is compatible with Google Sheets and LibreOffice Calc without compatibility mode warnings. Converting XLS to XLSX future-proofs your spreadsheets.

Open XLS to XLSX Converter

Step-by-step instructions

  1. 1

    Upload your XLS file

    Select your .xls file. Excel 97–2003 format files, output from older accounting software, and database exports often arrive as XLS. The converter reads the binary XLS format and prepares it for output.

    Go to converter
  2. 2

    Choose XLSX as the output format

    Select XLSX. The converter faithfully maps XLS data to XLSX — formulas, named ranges, conditional formatting, charts, pivot tables, and merged cells are all preserved.

  3. 3

    Download and verify the XLSX

    Open the XLSX in Excel or Google Sheets. Check that formulas still calculate correctly and that charts render as expected. Most conversions are seamless; very old XLS files with macros (VBA) may need attention.

Why convert XLS to XLSX?

XLS is Excel's legacy binary format. XLSX is the open XML standard that every modern spreadsheet application reads natively. Converting from XLS to XLSX is low-risk, usually seamless, and permanently modernizes your data.

Your files never leave your device

FormatDrop runs the conversion engine entirely inside your browser using WebAssembly. No file upload. No server. Nothing stored. You can verify this by opening DevTools → Network tab and watching: zero upload requests.

Frequently asked questions

Will macros (VBA) survive XLS to XLSX conversion?
Standard XLSX files do not support VBA macros — you need XLSM (Excel Macro-Enabled Workbook) for that. If your XLS has macros, save as XLSM in Excel (Save As → Excel Macro-Enabled Workbook) to preserve them. Converting to plain XLSX drops the macros.
How do I bulk convert XLS to XLSX with Python?
Use openpyxl: `import glob; from openpyxl import load_workbook; [wb.save(f[:-3]+'xlsx') for f in glob.glob('*.xls') for wb in [load_workbook(f)]]`. Or use libreoffice: `libreoffice --headless --convert-to xlsx *.xls`.
I have password-protected XLS files — can they be converted?
Password-protected files must be unlocked before conversion. In Excel: open the file with the password, go to Review → Unprotect Sheet/Workbook, then save as XLSX. Online converters cannot handle password-protected files.
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