Convert Excel (XLSX) to CSV online for free. Export spreadsheet data as comma-separated values. Fast, secure — no signup, no software to install.
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Checking files and selected output formats.
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XLSX → CSV is the "get this data out of Excel into something else" conversion — importing to a database, a Python pandas notebook, a marketing tool, or another SaaS. Only exports one sheet at a time; multi-sheet XLSX workbooks need one conversion per sheet. Loses formulas (values only), formatting, and cell colours.
CSV is the lowest-common-denominator data exchange format — every spreadsheet app, database, and analytics tool accepts it. Convert to CSV when you need to move tabular data between systems (importing into Google Sheets, uploading to a database, feeding into pandas / R). Loses formulas, formatting, and multi-sheet structure that XLSX preserves.
Technical comparison of the two formats — useful for deciding which to use, or for confirming what changes during conversion.
| Property | XLSX | CSV |
|---|---|---|
| Full name | Microsoft Excel (Open XML) | Comma-Separated Values |
| Year introduced | 2007 | 1972 |
| Developer / standard body | Microsoft | IBM (informal) |
| MIME type | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet | text/csv |
| File extension | .xlsx | .csv |
| Compression | ZIP-compressed XML | None |
| Color / data depth | N/A | N/A |
| Max dimensions / size | 1,048,576 rows × 16,384 columns | Unlimited |
| Transparency | No | No |
| Animation | No | No |
| Standard / specification | ECMA-376 / ISO/IEC 29500 | IETF RFC 4180 |
| Best for | Modern Excel spreadsheets, data analysis | Data interchange, database imports, ETL pipelines |
XLSX (Excel Open XML Spreadsheet) is the default file format for Microsoft Excel 2007 and later. Built on the Office Open XML standard (ECMA-376, ISO/IEC 29500), it uses ZIP-compressed XML files to store spreadsheet data, formulas, formatting, charts, and pivot tables. XLSX replaced the legacy XLS binary format with a more efficient, recoverable, and interoperable architecture.
XLSX supports over one million rows and 16,000 columns per worksheet, 500+ built-in functions, conditional formatting, data validation, and advanced chart types. The format is natively supported by Microsoft Excel, Google Sheets, Apple Numbers, LibreOffice Calc, and most modern spreadsheet applications. XLSX is the global standard for financial modeling, data analysis, reporting, and business intelligence workflows.
Quick answers about compatibility, quality, metadata handling, and the most common reasons to convert XLSX files to CSV.
