Only one sheet fits in a CSV
CSV has no concept of multiple sheets. Pick the sheet you need; if you need several, convert the workbook once per sheet.
Convert Excel to CSV
You do not need Excel installed to get a CSV out of an .xlsx file. This converter unzips the workbook, reads the sheet you pick, and writes a clean delimited file — useful when you are on a machine without Office, or automating a handoff.
- Runs in your browser
- No signup
- No upload
- Free
ExcelCSV
Runs on your deviceCSV
Options
Reading Excel
Auto-detect reads the first rows and picks the separator that splits them consistently.
Turn off when the file starts straight into data. Columns are then named column_1, column_2, and so on.
Turns "42" into a number and "true" into a boolean. Values with leading zeros stay text so IDs and zip codes survive.
Which worksheet to convert. Filled in once the workbook is read.
Dotted path to the array of records, such as data.items. Leave empty to use the whole document.
Turns {"user":{"id":7}} into a user.id column. Arrays are kept as JSON text.
Pick the encoding the file was written in. Wrong encoding shows up as garbled accents.
Comma-separated words that should become null instead of text.
Writing CSV
Snappy is the default across Spark, DuckDB and pandas. Gzip is smaller but slower to read.
Turns a user.id column back into {"user":{"id":7}}.
Excel needs a byte order mark to open UTF-8 files with accents correctly.
Rows per row group. Larger groups compress better; smaller groups let readers skip more.
Converting…
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Work with Parquet as well?See ParquetReader with ParquetReader — opens Parquet files directly.What happens
How this converter handles Excel to CSV
- Unzips the .xlsx container and lists every worksheet so you can choose the right one.
- Reads cell values with their types, so dates stay dates and numbers stay numbers rather than becoming display text.
- Uses the first row as the header, unless you turn that off.
- Writes RFC 4180 CSV with your chosen delimiter, and optionally a BOM.
Format differences
Excel vs CSV
Spreadsheet workbooks with sheets, formatting and cell types. Plain text rows that open anywhere, with no types and no schema.
| Excel | CSV | |
|---|---|---|
| Type information | Per cell — text, number, date, boolean | None — every value is text |
| Structure | Sheets of rows and columns | Flat rows and columns |
| Compression | Zipped XML | None |
| Typical file size | Smaller than CSV, larger than Parquet | Baseline (100%) |
| Schema | None beyond the header row | Header row at best |
| Human-readable | Only in a spreadsheet app | Yes, in any text editor |
| Tool support | Excel, Google Sheets, LibreOffice | Universal |
Worth knowing
What to watch out for
Formulas become their results
The converter reads the cached value Excel stored, not the formula. That is almost always what you want, but a workbook saved by a tool that did not compute values may show blanks.
Formatting is display, not data
Colours, merged cells, column widths and conditional formatting do not exist in CSV. A merged cell contributes its value once and leaves the covered cells empty.
When you need this
Common reasons to convert Excel to CSV
Feeding a script or an import job
Most command line tools and bulk importers read CSV and have no .xlsx support.
Getting data off a machine without Office
A browser is enough. No licence and no LibreOffice install required.
Version-controlling tabular data
CSV diffs line by line in Git. A binary .xlsx does not diff at all.
FAQ
Excel to CSV questions
Is my workbook uploaded?
No. The conversion runs in your browser using WebAssembly and JavaScript. The file is read from your disk into a Web Worker, converted in memory, and handed back as a download. It is never sent to a server, so there is nothing for us to store, log or leak.
Can I convert the older .xls format?
No. Only the modern .xlsx and .xlsm formats are supported. Legacy .xls is a completely different binary format; re-save it as .xlsx first in Excel, LibreOffice or Google Sheets.
How do I pick which sheet to convert?
Drop the file and the sheet list is read from the workbook. Choose from the Sheet dropdown in the input options. Without a choice, the first sheet is used and the conversion warns you that others were skipped.
Why do my accented characters look wrong when I reopen the CSV in Excel?
Excel needs a byte order mark to recognise UTF-8. Turn on "Add BOM for Excel" in the output options and it opens correctly.
Are dates preserved?
Dates are read as real dates and written as ISO-8601 text, which sorts correctly and parses unambiguously — unlike Excel’s locale-dependent display format.
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