How do XLS and CSVcompare? Here's everything you need to know to choose the right format — and how to convert between them.
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 While superseded by XLSX, many existing spreadsheets and enterprise systems still use this format.
Comma-Separated Values
CSV is the simplest tabular data format — rows of values separated by commas. It's the universal exchange format for data between databases, spreadsheets, and programming languages.
| Specification | XLS | CSV |
|---|---|---|
| Full name | Microsoft Excel Spreadsheet (Legacy) | Comma-Separated Values |
| Extension | .xls | .csv |
| MIME type | application/vnd.ms-excel | text/csv |
| Category | Document | Document |
| Developer | Microsoft | IBM (original concept) |
| Year introduced | 1987 | 1972 |
XLS and CSV serve different purposes. XLS is ideal for legacy spreadsheet compatibility, while CSV excels at data import and export.
Need to switch formats? Convert for free with SquishConvert.