vs
xlsx
CSV vs XLSX: plain data or a full spreadsheet?
A clear, practical comparison with a straight answer.
Use CSV when you are exporting or importing plain data between different programs or databases and want the widest compatibility. Use XLSX when the file needs formulas, formatting, charts or more than one sheet.
CSV is about as simple as a file can be: rows of text separated by commas, nothing else. XLSX is a full spreadsheet file, capable of formulas, cell formatting, charts and multiple sheets, all zipped up as XML.
That simplicity is CSV's strength when data needs to move between completely different systems. XLSX's extra structure is worth the larger file the moment you need the spreadsheet to actually calculate something.
.csv vs .xlsx at a glance
| .csv | .xlsx | |
|---|---|---|
| Formulas | No | Yes |
| Cell formatting | No | Yes |
| Multiple sheets | No, one table per file | Yes |
| File size for the same data | Smaller | Larger |
| Compatibility | Extremely wide, any program or database | Wide, needs a spreadsheet app |
| Best for | Data exchange and imports | Working spreadsheets with calculations |
Frequently asked questions
Can I convert a CSV to XLSX without losing data?
Yes, the values transfer directly. You just will not gain formulas or formatting automatically, those have to be added afterward.
Why does my XLSX file look wrong when saved as CSV?
CSV cannot store formulas, formatting, charts or multiple sheets, so saving to CSV keeps only the calculated values from the active sheet.