Format comparison
XLSX vs CSV
How do XLSX and CSVcompare? Here's everything you need to know to choose the right format — and how to convert between them.
.xlsx
Full guide →Office Open XML Spreadsheet
XLSX is the default format for Microsoft Excel spreadsheets. It supports complex formulas, charts, pivot tables, and large datasets. It's the industry standard for data analysis and financial modeling.
.csv
Full guide →Comma-Separated Values
CSV is the simplest tabular data format — rows of values separated by commas. It's the universal exchange format for data between databases, spreadsheets, and programming languages.
| Specification | XLSX | CSV |
|---|---|---|
| Full name | Office Open XML Spreadsheet | Comma-Separated Values |
| Extension | .xlsx | .csv |
| MIME type | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet | text/csv |
| Category | Document | Document |
| Developer | Microsoft | IBM (original concept) |
| Year introduced | 2007 | 1972 |
XLSX advantages
- Powerful formula and calculation engine
- Supports charts, pivot tables, and macros
- Industry standard for business data
- Compatible with Google Sheets and LibreOffice
XLSX limitations
- Complex format for simple data
- Can be slow with very large datasets
- Formatting issues between applications
- Requires office software for full features
CSV advantages
- Universal data exchange format
- Human-readable plain text
- Tiny file sizes
- Supported by every data tool
CSV limitations
- No formatting or styling
- No data types — everything is text
- Encoding and delimiter issues common
- No support for multiple sheets or formulas
Which should you use?
XLSX and CSV serve different purposes. XLSX is ideal for financial reports and budgets, while CSV excels at data import and export.
Best uses for XLSX
Financial reports and budgets
Data analysis and modeling
Inventory and project tracking
Survey results and data collection
Best uses for CSV
Data import and export
Database migrations
API data exchange
Data science and analysis pipelines
Convert between XLSX and CSV
Need to switch formats? Convert for free with SquishConvert.