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XLSX vs CSV

Comparing Microsoft Excel Open XML Spreadsheet and Comma-Separated Values — which format should you use?

XLSXCSV
Full NameMicrosoft Excel Open XML SpreadsheetComma-Separated Values
Extension.xlsx.csv
MIME Typeapplication/vnd.openxmlformats-officedocument.spreadsheetml.sheettext/csv
Categorydocumentdata

XLSX Pros

  • +Industry standard for spreadsheets
  • +Supports formulas, charts, macros
  • +Smaller than XLS (ZIP compressed)
  • +Compatible with Google Sheets, LibreOffice

XLSX Cons

  • -Binary content can be hard to diff/merge
  • -Macro-enabled versions (.xlsm) can be security risks
  • -Complex for simple data (use CSV instead)
  • -Proprietary format specification

CSV Pros

  • +Universally compatible
  • +Human-readable plain text
  • +Tiny file sizes
  • +Easy to generate and parse programmatically

CSV Cons

  • -No data type information (everything is text)
  • -No standard for encoding or escaping
  • -No support for hierarchical data
  • -No formatting, formulas, or multiple sheets

Use XLSX when...

  • -Financial reports and budgets
  • -Data analysis and modeling
  • -Business reporting
  • -Inventory tracking

Use CSV when...

  • -Data export/import between applications
  • -Database dumps
  • -Spreadsheet data exchange
  • -Data analysis and reporting