How do XLSX and XLScompare? Here's everything you need to know to choose the right format — and how to convert between them.
Office Open XML Spreadsheet
XLSX is the default format for Microsoft Excel spreadsheets. It supports complex formulas, charts, pivot tables, and large datasets. It's the industry standard for data analysis and financial modeling.
Microsoft Excel Spreadsheet (Legacy)
XLS is the legacy binary format used by Microsoft Excel before 2007. While superseded by XLSX, many existing spreadsheets and enterprise systems still use this format.
| Specification | XLSX | XLS |
|---|---|---|
| Full name | Office Open XML Spreadsheet | Microsoft Excel Spreadsheet (Legacy) |
| Extension | .xlsx | .xls |
| MIME type | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet | application/vnd.ms-excel |
| Category | Document | Document |
| Developer | Microsoft | Microsoft |
| Year introduced | 2007 | 1987 |
XLSX and XLS serve different purposes. XLSX is ideal for financial reports and budgets, while XLS excels at legacy spreadsheet compatibility.
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