XLS vs XLSX, side by side
| XLS | XLSX | |
|---|---|---|
| Full name | Microsoft Excel (legacy) | Microsoft Excel |
| Type | Spreadsheet | Spreadsheet |
| Compression | Lossless | Lossless |
| Best for | legacy spreadsheets; converted to XLSX or CSV | data, calculations and shared spreadsheets |
Choose XLS if…
…you need legacy spreadsheets; converted to XLSX or CSV.
Choose XLSX if…
…you need data, calculations and shared spreadsheets.
Convert between them
Frequently asked questions
What's the difference between XLS and XLSX?
Microsoft Excel (legacy) (XLS) is lossless and best for legacy spreadsheets; converted to XLSX or CSV. Microsoft Excel (XLSX) is lossless and best for data, calculations and shared spreadsheets.
Is XLS better than XLSX?
Neither is universally better — it depends on your use case. Choose XLS for legacy spreadsheets; choose XLSX for data.
Should I use XLS or XLSX?
Use XLS when you need legacy spreadsheets. Use XLSX when you need data.
Can I convert XLS to XLSX?
Yes — you can convert XLS to XLSX (and back) for free, in seconds, right here.
Last updated July 2026