XLSX vs CSV: what's the difference?
XLSX is Excel's full workbook format; CSV is plain text. Compare sheets, formatting, formulas, size limits and compatibility, and learn when to use each.
XLSX and CSV both hold tables of data, but they're very different files. XLSX is Excel's full workbook format. CSV is plain text with commas between the values. Here's how they compare and when to use each.
XLSX vs CSV at a glance
| Feature | XLSX | CSV |
|---|---|---|
| What it is | A zip file of XML documents (Office Open XML) | Plain text: one line per row, values separated by commas |
| Sheets | Many sheets in one file | One table per file |
| Formatting | Fonts, colors, borders, column widths, number formats | None |
| Formulas | Kept and recalculated | Only the results |
| Charts, images, comments | Yes | No |
| Data types | Numbers, dates, text and booleans are stored as types | Everything is text; the program opening it guesses |
| Size limit | 1,048,576 rows × 16,384 columns per sheet | No limit in the format (Excel opens the first 1,048,576 rows) |
| Opens in | Excel, Google Sheets, Numbers, LibreOffice | Almost anything: spreadsheets, databases, text editors, code |
| Readable by people | Only in a spreadsheet app | Yes, in any text editor |
| File size | Compressed, usually smaller | Often larger for the same data |
When to use XLSX
- You're still working on the data and need formulas, formatting or several sheets.
- You're sharing a report people will read in Excel, with charts, totals and colors.
- Data types matter, and you don't want dates or long IDs reinterpreted.
When to use CSV
- You're importing into another system: an email platform, CRM, online store, accounting tool or database. Most of them want CSV.
- You're feeding data to a script or program. CSV is easy to read in any programming language.
- You want a simple, long-lasting file that any software can open in 20 years.
- You're tracking changes in version control, where text files show clear differences.
What about XLSM, XLS and XLSB?
- XLSM is XLSX with macros allowed. It converts to CSV just the same; the macros are simply left out.
- XLS is the old binary format used before Excel 2007. Open it in Excel or Google Sheets and save as XLSX or CSV.
- XLSB is a binary version of XLSX that loads faster for huge workbooks. Save it as XLSX before converting it in a browser.
Converting between them
To go from XLSX to CSV, use the converter on our home page, which can do every sheet at once, or Excel's Save As (one sheet at a time). To go from CSV back to XLSX, open the CSV in Excel and save it as an Excel Workbook (*.xlsx). Use Data › From Text/CSV if you need to keep leading zeros or accents. Here's why.
Skip the steps: convert every sheet to CSV in your browser, free.
Convert XLSX to CSV