XLSX vs CSV — which one for business data?
xlsx carries formatting, formulas, and multiple sheets. CSV is the minimal text-only table. Pick based on the consumer.
Quick verdict
- Humans editing in Excel → xlsx.
- Programmatic processing or database ingestion → CSV.
- Long-term archival → CSV (every tool handles it).
Side-by-side
| Property | xlsx | CSV |
|---|---|---|
| Formulas | Yes | No |
| Formatting (colour, bold) | Yes | No |
| Multiple sheets | Yes | One table per file |
| File size | Moderate | Small |
| Encoding | UTF-8 (internal XML) | Implementation-defined (UTF-8 / Shift_JIS) |
Conversion gotchas
- xlsx → CSV loses formatting, formulas, and pivots.
- CSV → xlsx sees Excel auto-infer types — leading zeros disappear, strings get parsed as dates.
- For automation, use
pandasoropenpyxlwith explicit column types.