What CSV to Excel does
Upload a CSV — an export from a database, a bank, a web form, a ticketing system or any script — and get a real Excel workbook (.xlsx) with the data in a sheet, numbers stored as numbers and text as text. Opening a CSV directly in Excel often mangles it: leading zeros vanish from phone numbers and postcodes, dates flip between day-month and month-day, long digit strings become scientific notation, and UTF-8 accents turn to garbage. This converter parses the CSV properly and writes a native workbook, in your browser, without uploading the data.
What the parser handles
| Feature | Handling |
|---|---|
| Delimiter | Comma, semicolon, tab or pipe — detected automatically |
| Quoted fields | Commas, line breaks and doubled quotes inside quotes are respected |
| Encoding | UTF-8 (with or without BOM); Latin-1 is decoded as UTF-8 and may need re-saving |
| Header row | Written as the first row (freeze it in Excel if you like) |
| Numbers | Stored as numeric cells so sums and sorting work |
| Dates | Recognised ISO dates (2026-03-01) become Excel dates; ambiguous formats stay text |
| Leading zeros, long IDs | Kept as text when the value would otherwise change |
Why not just open the CSV in Excel?
- Excel guesses the delimiter from your locale, so a comma CSV on a European PC lands in one column.
- Values such as
00123,1E5and3/4are silently converted to numbers, dates or fractions. - Non-ASCII text is read in the system code page unless the file has a BOM, producing
éforé. - Saving back to CSV from Excel loses formulas, formats and sheets you may have added.
A native .xlsx sidesteps all of this and can be shared with colleagues who will simply double-click it.
Common uses
- Sending a data export to a manager or client as a proper spreadsheet.
- Preparing a bank or payment-gateway CSV for reconciliation in Excel.
- Converting survey or form results for analysis with pivot tables.
- Turning log or report CSVs into a workbook for filtering and charts.
- Importing contact lists into systems that accept .xlsx only.
Tips
- To combine several CSVs into one workbook, convert them separately and copy the sheets together in Excel, or merge the CSVs first with the CSV tools on this site.
- The sheet is named after the file; rename it in Excel if needed.
- Column widths are set to fit the longest value in each column, up to a limit.
- For the reverse direction, use XLSX to CSV.
Frequently asked questions
My numbers ended up as text.
Values with leading zeros, thousands separators in an unusual locale, or currency symbols are kept as text to avoid corruption. Use Excel's Text to Columns or VALUE() to convert if you are sure.
Accented characters look wrong.
The CSV is probably Latin-1 or Windows-1252, not UTF-8. Re-save it as UTF-8 in a text editor, or open it in Excel via Data → From Text with the right encoding.
Can it handle a very large CSV?
Files of a few hundred thousand rows convert in seconds on a desktop. Excel's own limit is 1,048,576 rows per sheet.
Does it support .xls (old Excel)?
Output is .xlsx, which every Excel since 2007 opens. Save as .xls in Excel if a legacy system needs it.
Are formulas created?
No. CSV contains values only; the workbook contains those values.
Is my data uploaded?
No. Parsing and workbook generation run in your browser with SheetJS.