CONVERT XLSX → CSV (XLSX to CSV)
Export Excel spreadsheet data to universal CSV format for data processing.
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HOW TO CONVERT XLSX → CSV
Upload the XLSX
Drop your .xlsx workbook. All sheets are detected.
Extract cell values
Formula cells resolve to their last cached value; formatting is stripped.
Download the CSV
Single-sheet workbooks return one CSV; multi-sheet workbooks return a ZIP of CSVs.
Converting XLSX to CSV extracts tabular data from an Excel workbook into a plain-text delimited file ready for analytics tools, databases, scripting pipelines, and data-exchange protocols that cannot read XLSX. Our converter handles multi-sheet workbooks (emitting one CSV per sheet when needed), preserves formula evaluation (using the last cached values), and writes UTF-8 output with proper RFC 4180 quoting.
Why convert XLSX to CSV
XLSX is a zipped XML bundle with formatting, formulas, and multiple sheets. Many tools — command-line processors, data-loading utilities, SQL import jobs — require a stripped-down CSV. Converting upfront skips the preview pane in Python pandas or SQL ETL tools that would otherwise stall on formatted cells.
XLSX vs CSV — Technical specifications
Side-by-side comparison of the technical details.
XLSX
- MIME type
- application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
- Container
- ZIP (Office Open XML)
- Max rows
- 1,048,576
- Max columns
- 16,384
- Released in
- Microsoft Office 2007
- Variants
- .xlsx, .xlsm (macros), .xlsb (binary)
- MIME Type
- application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
- Extension
- .xlsx
- Category
- Spreadsheets & Data
- Full Name
- Excel Spreadsheet
- Conversion Engine
- LIBREOFFICE
CSV
- MIME type
- text/csv
- MIME Type
- text/csv
- Extension
- .csv
- Category
- Spreadsheets & Data
- Full Name
- CSV (Comma-Separated Values)
- Conversion Engine
- LIBREOFFICE
- Specification
- RFC 4180 (informational)
- Typical separator
- Comma (;), semicolon, tab, pipe
- Typical encoding
- UTF-8, Windows-1252, ISO-8859-1
- Line endings
- LF (Unix), CRLF (Windows)
| Specification | XLSX | CSV |
|---|---|---|
| MIME type | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet | text/csv |
| Container | ZIP (Office Open XML) | — |
| Max rows | 1,048,576 | — |
| Max columns | 16,384 | — |
| Released in | Microsoft Office 2007 | — |
| Variants | .xlsx, .xlsm (macros), .xlsb (binary) | — |
| MIME Type | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet | text/csv |
| Extension | .xlsx | .csv |
| Category | Spreadsheets & Data | Spreadsheets & Data |
| Full Name | Excel Spreadsheet | CSV (Comma-Separated Values) |
| Conversion Engine | LIBREOFFICE | LIBREOFFICE |
| Specification | — | RFC 4180 (informational) |
| Typical separator | — | Comma (;), semicolon, tab, pipe |
| Typical encoding | — | UTF-8, Windows-1252, ISO-8859-1 |
| Line endings | — | LF (Unix), CRLF (Windows) |
XLSX vs CSV — Strengths and limitations
What each format does best, and where it falls short.
XLSX Strengths
- Much smaller than legacy .xls files thanks to ZIP + XML.
- Human-readable structure — easy to extract data programmatically.
- Supports macros (as .xlsm variant), charts, pivot tables, conditional formatting.
- Universal support: Excel, LibreOffice, Google Sheets, Numbers, pandas.
- ISO/IEC 29500 standardized.
Limitations
- Macros in .xlsm are a common malware vector — disabled by default in Office.
- 1M-row limit is a cultural problem — people put too much data in Excel.
- Subtle formula differences between Excel, LibreOffice, and Sheets.
CSV Strengths
- Universally readable — every spreadsheet, database, and programming language.
- Human-readable in any text editor.
- Stream-friendly — can process terabytes with constant memory.
- Git-friendly — clean diffs of row changes.
- Tiny overhead vs columnar data structures for simple data.
Limitations
- No standard — quoting, escaping, encoding, and separators vary wildly.
- No type information: 0042 might be an integer, a string, or an error.
- Leading zeros and large numbers often get mangled by Excel auto-conversion.
Quality & Compatibility
Dates are written as ISO 8601 strings; numbers retain full precision. Formulas output their last evaluated value — if the XLSX was never opened in Excel after editing, formulas may not have a cached value. Multi-sheet workbooks become one CSV per sheet in a ZIP.
Tips for Best Results
- Open the XLSX in Excel and save once before converting if you suspect uncached formulas.
- Multi-sheet workbooks become a ZIP of CSVs — one file per sheet.
- For locale-specific CSVs (comma vs semicolon), use the advanced delimiter option.
Frequently Asked Questions
Upload your XLSX file to KaijuConverter and select CSV as the output format. The first sheet will be exported with proper column separation and encoding.
CSV only stores values, not formulas. The conversion exports the calculated values. Keep your original XLSX if you need to preserve formulas.
Yes. The free tier accepts files up to 25 MB without registration, email capture or watermarks; paid plans go up to 2 GB. Paid plans raise the size cap, enable batch conversions and provide a REST API for automation, but nothing on the free tier is quality-limited — the output is exactly the same as on any paid plan.
They are resolved to their last cached value. If the XLSX has never been opened in Excel after edits, some cells may be blank — open and save in Excel first to force evaluation.
Uploads run over HTTPS, files are processed in isolated containers, and both the source XLSX and the CSV output are auto-deleted within two hours. No account is required, file contents are never logged, and KaijuConverter does not use uploads for AI training. The paid plan adds a signable data-processing agreement for regulated workflows.
Each sheet becomes its own CSV file, named after the sheet. All CSVs are packaged into a single ZIP download.
Most files finish in well under a minute. Small images and documents are typically ready in a few seconds; large video or audio files scale roughly with duration. Upload speed from your network is usually the dominant factor, not server time.
Yes. The output is UTF-8 with a BOM so Excel opens it with correct character rendering for accented, Asian, and other non-ASCII text.
Dates are written as ISO 8601 (YYYY-MM-DD) and numbers in dot-decimal format. This keeps data portable across tools and locales.
Excel Spreadsheet
Source formatXLSX is the modern Microsoft Excel format based on Open XML. It is the industry standard for spreadsheets, supporting formulas, charts, pivot tables, and conditional formatting.
CSV (Comma-Separated Values)
Target formatCSV is a simple text-based format for tabular data where values are separated by commas. It is the universal interchange format for data between spreadsheet applications, databases, and programming languages.
Going the other way? Convert CSV back to XLSX with the same engine.
Common Use Cases
Data engineering pipelines
Airflow, Spark, and pandas ingest CSV natively; XLSX needs a preprocessing step.
Database imports
PostgreSQL COPY and MySQL LOAD DATA operate on CSV; XLSX needs conversion first.
Analytics tool ingestion
Many BI tools prefer CSV for bulk imports to avoid cell-formatting parsing.
Git-tracked data
CSV diffs cleanly in Git; XLSX diffs are unreadable binary noise.
XLSX vs CSV — Typical file sizes
Approximate file sizes for common scenarios.
- Small budget spreadsheet 20–80 KB
- Financial model with charts 1–10 MB
- Large dataset (100k rows) 10–50 MB
- Contact export (1000 rows) 100–300 KB
- Analytics export (100k rows) 10–100 MB
- Large dataset (1M rows) 100 MB – 1 GB
Sensitive Documents, Scanned OCR, or 500+ Pages?
For legally sensitive archives that must never leave your local network, or multi-hundred page scanned PDFs needing optical character recognition, local document workstations ensure full compliance.
One-time payment with zero recurring commitment: convert files up to 1 GB, OCR, PDF/A, and .ZIP batches for 24 hours.
Full 7 days of unlimited conversions, up to 2 GB per file, 100% ad-free with zero subscription.
High-throughput enterprise pipeline for files up to 2,048 MB, 50-file batches, ISO PDF/A, and priority processing.
Offline conversion for multi-hundred page contracts, spreadsheets, and local optical extraction.
High-accuracy legal OCR, certified PDF/A archiving, and compliant document redaction.
Related comparisons
See these formats side by side to understand which fits your use case best.
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Read guide →CSV Format: The Complete Guide to Comma-Separated Values
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Read guide →
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