XLSX: Excel Open XML Spreadsheet

What is XLSX?

XLSX is Microsoft Excel's XML-based spreadsheet format introduced with Office 2007. Based on the Office Open XML standard, XLSX replaced the older binary XLS format, offering better compression, improved data recovery, and enhanced security.

As a ZIP container holding XML files, XLSX is more efficient and supports larger worksheets (1,048,576 rows × 16,384 columns) compared to its predecessor.

Key Features

• XML-Based: Open standard, easier to parse
• Better Compression: Smaller file sizes than XLS
• Large Capacity: Over 1 million rows per sheet
• Advanced Formulas: 400+ built-in functions
• Rich Formatting: Styles, conditional formatting, charts
• Macros: VBA support (in .xlsm)
• Data Validation: Input constraints and rules
• Pivot Tables: Dynamic data analysis

Common Uses

• Business financial reports and budgets
• Data analysis and statistics
• Project management tracking
• Inventory and sales records
• Scientific data logging
• Database exports and imports

Advantages

• Industry standard for spreadsheets
• Smaller file sizes than XLS
• Better data recovery from corruption
• Wide software compatibility
• Supports advanced Excel features
• Open XML standard

Limitations

• Requires compatible software
• Large files with lots of formatting
• Version compatibility issues
• Slower to open than simpler formats
• Macros pose security risks

Technical Information

XLSX files are ZIP archives containing XML files that define worksheets, styles, formulas, and metadata. This open format allows third-party tools to read and write Excel files without needing Excel itself.