Convert each worksheet to CSV with delimiter choice and a ZIP for multi-sheet workbooks.
XLSX · XLS · ODS→ CSVModerate on device
CSV to Excel
Combine CSVs into a clean workbook, one sheet per file, with delimiter detection you can override.
Processed locallyIn: CSV, TSVOut: XLSX
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How to use csv to excel
Select one or more CSV/TSV files.
The delimiter and header row are detected; adjust if needed.
Each file becomes a worksheet in a brand-new workbook.
The output is reparsed to verify sheet and row counts, then downloads.
What this tool does
- Multiple CSVs into one workbook, one sheet per file
- Automatic delimiter detection (comma, semicolon, tab, pipe) with manual override
- UTF-8 BOM handling
- Fresh workbook output with no hidden structures, macros, or metadata
How the result is verified
The generated workbook is reparsed locally; sheet count and per-sheet row counts must match the parsed inputs.
Frequently asked questions
Will my ID numbers lose leading zeros?
By default numeric-looking values become numbers, which drops leading zeros — the same thing Excel does. Enable 'keep values as text' to preserve them exactly.
Is my file uploaded to a server?
No. The file is opened with your browser's File API and processed by code running in your tab. You can confirm this yourself: open your browser's developer tools, watch the Network panel, and process a file — no request carries your file's bytes. See our How it works page for a step-by-step verification guide.
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