CSV to Excel Converter — Keep Leading Zeros, Dates and Accents
Turn CSV or TSV files into a real Excel workbook with numbers, dates and leading zeros kept right — several files become sheets of one workbook.
Free, with no sign-up and no watermark. The file is processed in your browser and never uploaded.
Turn CSV, TSV or delimited text files into a real Excel workbook (.xlsx). Numbers become numbers, dates become real Excel dates, and IDs such as 007, phone numbers like +91… and 16-digit card or account numbers stay exactly as typed — the classic problems you get when you double-click a CSV in Excel.
The text encoding (UTF-8, UTF-16 or the Windows-1252 that older Excel saves) and the separator are detected automatically, and you can add several CSV files to get one workbook with a sheet per file.
Step by step
- Add your files: Click Upload CSV files or drop them in. Add several to combine them; drag to change the sheet order.
- Check the preview: The first rows are shown so you can confirm the columns split correctly. If not, pick the Separator or Text encoding yourself.
- Choose how values are read: Pick the Decimal mark used in the file (1,234.56 or 1.234,56), and keep Keep IDs as text and Turn dates … into real Excel dates on unless you need otherwise.
- Convert: Click Convert to Excel. One file downloads as .xlsx; several files become one workbook, or a ZIP of workbooks if you untick Combine all files.
Handy for
Bank and UPI statements
Open exported statements without Excel turning account numbers into 1.23E+15.
Customer lists
Keep PIN codes, phone numbers and IDs with leading zeros intact.
European data
Read semicolon-separated files with decimal commas correctly.
Monthly reports
Combine twelve monthly CSVs into one workbook, one sheet per month.
Good to know
The header row gets filter buttons in Excel; untick First row is a header if your file has no header.
Dates are recognised in ISO (2024-03-31) and day-first (31/03/2024) form. US month-first dates stay as text so they are never swapped silently.
Excel sheets hold at most 1,048,576 rows — larger files need splitting first.
Questions
Why does Excel lose my leading zeros when I open a CSV directly?
Excel guesses every value’s type and treats “007” as the number 7. This tool decides types itself and stores IDs, phone numbers and very long numbers as text, so nothing changes.
My accented letters showed as é before — will this fix it?
Yes. The encoding is detected (including Windows-1252 from older Excel) and decoded properly before the workbook is written. You can also force an encoding.
Are styles or formulas added?
No — a CSV has no formatting or formulas. You get clean typed values, sensible column widths and filter buttons on the header.
Are my files uploaded?
No. Every conversion runs inside your browser on your own device. Your files are never sent to a server, so confidential spreadsheets, contracts and photos stay private.
More Office Formats tools
- Excel to CSV — Export one sheet or every sheet of an Excel, ODS or Numbers file to CSV with your choice of separator, dates and encoding.
- XLS to XLSX Converter — Convert spreadsheets between XLS, XLSX and ODS while keeping formulas, number formats, merged cells and every sheet.
- ODS to Excel — Convert OpenDocument spreadsheets from LibreOffice or OpenOffice to Excel XLSX, with formulas and sheets intact.
- ODT to PDF — Convert OpenDocument Text files to PDF with headings, lists, tables, images and real selectable text.
- ODT to Word — Turn OpenDocument Text files into editable Word documents with headings, lists, tables and images.
- RTF to PDF — Convert Rich Text Format files from WordPad or TextEdit to PDF or editable Word, keeping formatting and pictures.