Developer tool / 07
Excel to CSV Converter
Turn an .xlsx workbook into CSV, one sheet at a time, without uploading the file.
Excel to CSV Converter: TOEA unpacks the workbook and reads its sheet data directly, resolving the shared string table, keeping empty cells in place so columns stay aligned, and writing the result as quoted CSV. Runs 100% locally in your browser with zero server file uploads.
- Category
- Developer tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Up to 5 MB · nothing is uploaded
Dates and other formatted numbers
Excel stores a date as a count of days, so 1 January 2024 is 45292, and only the cell's number format makes it look like a date. Cells formatted as a date or time are written in ISO form: 2024-01-01, 2024-01-01 14:30:00 when there is a time, or 14:30:00 for a time on its own. Workbooks using the older 1904 date system are handled. Elapsed-time formats such as [h]:mm stay numbers. Other formats are not applied: percentages come out as decimals (0.25), and currency loses its symbol.
Cells that contain line breaks, commas, or quotes are quoted in the CSV, so a multi-line address stays one field. Import the file with a CSV-aware reader rather than splitting on lines.
Checking the export
Values also appear with their full stored precision, so a cell displayed as 0.3 can come out as 0.30000000000000004. Hidden rows and columns are exported like any others, and each merged area gives its value to the top-left cell only. Choose the sheet you need from the selector; the others are not included.
Compare the row count with the sheet before relying on the file. CSV to JSON turns the result into records for code, and CSV to Excel makes a workbook again.
How to use it
- Choose an .xlsx file.
- Pick a sheet if the workbook has several.
- Copy or download the CSV.
Privacy & limitations
The text is converted in your browser and never uploaded, which matters when the file is a config or an export you would rather not hand to a stranger. Reading is done with the browser's own decompression and this site's XML parser, so no spreadsheet library is loaded.
Related tools
Frequently asked questions
Are formulas evaluated?
No. A cell shows the result the spreadsheet last saved with it. A workbook written by a tool that does not calculate will show those cells as empty.
What happens to a row with gaps?
Skipped columns become empty cells, so the data stays aligned. Collapsing them would silently shift every value left.
Does formatting carry across?
Mostly not. CSV holds values only, so colours, fonts, merged cells, and most number formats are dropped. Cells formatted as dates or times are the exception: they come out as ISO dates such as 2024-03-01 rather than Excel's serial numbers.
Is .xls supported?
No, only the modern .xlsx format. Older files can be re-saved as .xlsx in any spreadsheet program.
Free tool · runs in your browser · no account required