CSV ⇔ Excel (XLSX) Converter
Turn a CSV file into an Excel workbook (.xlsx), or export a sheet of an Excel workbook as CSV. Everything happens in your browser, so your files are never uploaded. If you need JSON instead, use the CSV ⇔ JSON Converter; to only change a file's character encoding, try the Encoding Converter.
🔒 Runs in your browser · Your data is never sent to a server
Drag & drop a CSV (.csv / .tsv / .txt) here, or click to choose one
Drag & drop an .xlsx file here, or click to choose one
How to use
- Choose "CSV→Excel" or "Excel→CSV" with the switch above.
- Drag & drop a file or click to choose one (you can also paste text for CSV→Excel).
- Check the options. For Excel→CSV you can also pick which sheet to convert.
- Press "Convert and save as xlsx" or "Save CSV" to download the result.
Notes
- CSV→Excel writes the CSV into a single sheet with no formatting (column widths, colors, formulas and so on).
- Number-like values become number cells. Values with a leading zero (phone numbers, ZIP codes) and numbers with more than 15 digits and exponent notation such as 1e5 stay as text so they are not altered.
- Excel→CSV outputs only the calculated value of a formula. Display formats such as percentages, currency and thousands separators are not applied; the underlying value is written. Cells with a date or time format are written like 2026-10-10 or 2026-10-10 09:30:00.
- Merged cells, charts, images and macros are not reflected in the CSV. Hidden rows, columns and sheets are not treated specially: their values are exported and listed like any other.
- Legacy .xls files and password-protected workbooks are not supported.
- To open a CSV with Japanese text directly in Excel, save it as UTF-8 with BOM. When importing into another system, BOM-less UTF-8 is usually the better choice.
Glossary
XLSX
The workbook file format used by Excel 2007 and later. It is a ZIP archive of XML files and can hold multiple sheets.
CSV
Short for Comma-Separated Values, a plain-text format where columns are separated by commas or another delimiter. It carries no formatting or sheets, which makes it a common way to move data between Excel, Google Sheets and databases.
Shift_JIS
The character encoding that Japanese-language Excel uses when saving "CSV (comma delimited)". Reading it as UTF-8 produces garbled text, so this tool detects it automatically.
BOM
Short for Byte Order Mark, a 3-byte marker at the start of a UTF-8 file. With a BOM, Japanese-language Excel opens the CSV as UTF-8 correctly.
FAQ
My CSV shows garbled characters in Excel. What should I do?
Converting the CSV to xlsx here avoids encoding problems, since the tool auto-detects UTF-8 and Shift_JIS when reading. If you need to keep a CSV that opens correctly in Excel, use "Excel→CSV" with "Save as UTF-8 with BOM" checked.
Will leading zeros in phone numbers or ZIP codes be lost?
No. Values with a leading zero are stored as text cells, so they stay as they are. Numbers with more than 15 digits are also kept as text, because Excel would otherwise round them. You can change the cell format in Excel afterwards if you want numbers.
How are workbooks with multiple sheets handled?
In "Excel→CSV" you pick one sheet from the list and it is exported as CSV. A CSV file can only hold a single sheet, so all sheets cannot be exported in one go; export them one at a time.
Can I convert old .xls files or password-protected workbooks?
No, only .xlsx is supported. Open the .xls file or the protected workbook in Excel, remove the password, and use "Save As" to save a copy as .xlsx first.
Is my file uploaded anywhere?
No. The conversion runs entirely in your browser and the contents of your file are never sent to a server.
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