Convert CSV to Excel, or Excel to CSV

Formats and limits

Opens

CSV (.csv), TSV (.tsv), Text (.txt), Pasted text, Excel workbook (.xlsx, .xlsm)

Saves

Excel workbook (.xlsx) with one sheet, from a CSV; CSV in UTF-8 (.csv, or .tsv with the tab delimiter), from one sheet of a workbook

Size

Tested in Chromium (the engine Chrome and Edge use) on Linux with CSV files up to 80 MB and workbooks up to 27 MB; not tested yet at those sizes in Firefox or Safari. Each part of a workbook (a sheet, or the text its sheets share) may unzip to at most 128 MB, which for a sheet is about 350,000 rows of 10 short cells, and the parts one conversion reads to 256 MB in all. Past those limits, or when a sheet's CSV would hold more than 50 million cells, the page says why instead of converting. Excel's own limits apply: 1,048,576 rows, 16,384 columns and 32,767 characters in a cell.

How to use it

1. Choose, drop or paste a CSV, TSV or TXT file, or choose an Excel workbook (.xlsx or .xlsm). It's read at once.
2. Check the preview. For a CSV, change the delimiter if it was read wrongly; for a workbook with several sheets, choose the sheet.
3. For a CSV, choose whether plain numbers are stored as numbers; for a workbook, choose the CSV's delimiter and line endings.
4. Select Download Excel file (.xlsx) or Download CSV.

Known limitations

• Formulas aren't recalculated: the CSV gets the value each formula had when the workbook was last saved, and a formula saved without a value comes out empty.
• Only cell values are converted. Formatting, column widths, comments, charts, images and macros aren't read or written; macros in an .xlsm file are never run.
• Numbers come out as stored in the workbook, with full precision, not as formatted on screen: 1234.5 rather than $1,234.50.
• Dates and times become ISO 8601 text in the CSV (2026-10-18, 2026-10-18T13:30:00, 18:00:00), from either of Excel's two date systems; a duration formatted as [h]:mm:ss becomes hours:minutes:seconds (36:00:00).
• A merged area keeps its value in its top-left cell; the other cells of the area are empty.
• One sheet per conversion. Hidden sheets are listed and can be converted; chart sheets have no cells to convert.
• Old .xls workbooks, password-protected workbooks, .xlsb and .ods files aren't read: save them as .xlsx first.
• In a CSV made from a workbook, text that starts with =, +, - or @ is written as it is, and a spreadsheet app may read it as a formula when it opens the CSV.
• A CSV is read as in Fix CSV: unless it's valid UTF-8 or starts with a byte-order mark, its encoding is a guess you confirm, and a quoted cell that never closes stops the conversion.
• A workbook made here from a CSV of short cells unzips to about six times the CSV's size, so one made from a CSV over about 22 MB may be too large for this tool to convert back to CSV.

Questions