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Convert XLS to XLSX
Convert XLS to XLSX format — 100% browser-based, no upload required.
2 cores · low tier
Drop a file here or click to select
Format will be auto-detected
About these formats
Source
XLS
Microsoft Excel 97-2003Legacy Excel binary format. Limited to 65,536 rows and 256 columns, replaced by XLSX.
Best for
Legacy spreadsheet compatibilityOlder systems
Advantages
- + Legacy compatibility
- + Simple format
Limitations
- − Row/column limits
- − Outdated
- − No modern features
Target
XLSX
Microsoft Excel SpreadsheetStandard spreadsheet format with formulas, charts, pivot tables, and data analysis. Used across business and science.
Best for
Data analysisFinancial reportsBusiness dataCharts & formulas
Advantages
- + Formulas & functions
- + Charts
- + Data analysis
- + Wide support
Limitations
- − Requires Office software
- − Slow with large data
- − Complex format