CSV vs Excel (XLSX): Which Should You Use?
Use CSV when you're moving data between systems — databases, APIs, scripts, other people's tools. Use XLSX when humans need to read, edit, and calculate with the file in Excel. They look similar in Excel's grid, but under the hood they're very different formats.
Quick comparison
| Capability | CSV | XLSX |
|---|---|---|
| Formulas | No | Yes |
| Formatting (bold, color) | No | Yes |
| Multiple sheets | No | Yes |
| File size | Tiny | Larger |
| Universal compatibility | Yes | Excel/Sheets/etc only |
| Git-friendly diffs | Yes | No (binary) |
| Max rows | Unlimited | 1,048,576 |
When to convert XLSX → CSV
Before you import into a SQL database, before you feed it to a Python/R/JS script, before you send it through an API, or before you commit data to Git. The conversion strips formulas and formatting — you only keep the raw values.
In Excel: File → Save As → CSV UTF-8 (Comma delimited). In Google Sheets: File → Download → Comma-separated values.
When to convert CSV → XLSX
When a non-technical teammate needs to add formulas, color-code rows, or build a chart on top of the data. Just open the CSV in Excel and Save As Excel Workbook (.xlsx).
Frequently asked questions
Will I lose data converting XLSX to CSV?
You lose formulas, formatting, charts, and any non-active sheets. Cell values themselves are preserved.
Can CSV hold more rows than Excel?
Yes — CSV has no row limit. Excel caps at ~1M rows per sheet.