Convert CSV to Excel. Combine files into one workbook, no upload
A CSV opens in Excel, but it is not an Excel workbook and cannot retain formatting. Several related CSVs also mean several separate windows. This page gathers them into a real .xlsx workbook using SheetJS. One file produces one sheet; several files become named sheets in the same workbook. The data is packaged locally in your browser, and the result opens in Excel, Google Sheets, and LibreOffice.
How it works
- Drop one or more .csv files. Each becomes a sheet named after the file.
- They are assembled into a single .xlsx workbook on your device.
- Download the workbook and open it in Excel, Sheets, or LibreOffice.
Frequently asked questions
How do multiple CSVs become one file?
Each CSV you drop becomes a separate worksheet in one .xlsx workbook, with the tab named after the source file. Drop a single CSV and you get a one-sheet workbook. It is the quickest way to consolidate related exports into one spreadsheet.
Will numbers and dates be typed correctly?
Values that look like numbers are stored as numbers, so sums and sorting work in Excel rather than treating everything as text. Very ambiguous values (like long ID codes) can occasionally be misread. Check any column where exact formatting matters.
Is the CSV uploaded to build the Excel file?
No. The workbook is assembled by SheetJS running in your browser tab. Nothing is transmitted, which is what you want for exports containing customer, financial, or personnel data.
What Excel version does the output work with?
The output is standard .xlsx, opened by Excel 2007 and later, Google Sheets, LibreOffice, and Numbers. It is the modern, universally supported spreadsheet format.