XLS File

Microsoft Excel Workbook (.xls)

What is a XLS file?

An XLS file is the older Microsoft Excel workbook format used widely before XLSX. It can contain worksheets, formulas, charts, and formatting, but it’s a binary format (not the newer zipped XML structure used by XLSX).

Common uses

Older spreadsheets created with legacy Excel versions
Business reports, budgets, and tables in older systems
Archives of spreadsheet data shared over many years
Exports from older software that still outputs .xls
Workflows that require backward compatibility

How to open a XLS file

Windows: Microsoft Excel, LibreOffice Calc
macOS: Excel, LibreOffice Calc, Numbers (import)
Online: Google Sheets (upload/open) or Excel for the web
Tip: Convert to XLSX to reduce corruption risk and improve compatibility

Common problems

Formatting and formulas may differ in newer apps
File corruption after crashes or partial downloads
Macro-related concerns (some legacy files include VBA code)
Row/column limits (older .xls has smaller limits than .xlsx)
Protected sheets or passwords prevent editing

History

XLS was Excel’s standard workbook format for decades. In 2007, Microsoft introduced .xlsx (Office Open XML) as the default to improve structure, recovery, and interoperability. XLS files are still common because many older documents and systems continue to rely on them.