Change a CSV’s delimiter (semicolon ⇄ comma ⇄ tab)
A “CSV that won’t import” is very often just a delimiter mismatch: the file uses semicolons (the default Excel produces in most of Europe, where the comma is the decimal separator) and the importer insists on commas — or vice versa. The fix is not find-and-replace in a text editor: a file whose data contains commas (“Acme, Inc.”) will shatter into extra columns the moment you blindly swap characters, and quoted fields make it worse.
This tool re-delimits properly: the file is parsed with its current delimiter (auto-detected), then re-serialized with the one you choose — quoting recalculated for the new delimiter, so “Acme, Inc.” stays one field whether the file uses commas, semicolons, tabs or pipes. Locally, as always; the file never uploads.
Preset: the export panel opens set to the alternate delimiter — flip it as needed.
Drop a CSV, TSV or Excel file here
.csv · .tsv · .txt · .csv.gz · .xlsx — files up to 4 GB open here, in your browser. Nothing is uploaded; the file is read in place on your device.
Filters combine with AND. Use the search box for a quick any-column match. Regex filters use JavaScript syntax.
Untick to hide a column (hidden columns are left out of exports). Type to rename — renames apply to exports too.
Exports include your filters, sort, edits and cleanups. Hidden columns are left out; renamed headers apply. The file is generated on your device — nothing is sent anywhere.
How it works
- Drop the file. The current delimiter is auto-detected (check the toolbar if columns look wrong).
- Verify the grid shows proper columns — that proves the parse is right.
- In the export panel, pick the target: comma, semicolon, tab or pipe.
- Download. Quoting is recalculated for the new delimiter automatically.
Why Excel made your CSV semicolons in the first place
Excel delegates the “C” in CSV to Windows’ regional settings — specifically the List separator. In comma-decimal locales (Germany, France, Spain, Brazil, and most of continental Europe) the list separator defaults to a semicolon, because 3,14 already means π there and commas can’t double as field separators. So Save As CSV writes semicolons, the file crosses a border, and a comma-expecting importer reads every row as one giant column. Nobody did anything wrong; two regional conventions just met in a text file.
The durable fix in Excel is changing the system List separator (which also changes your formula argument separators — a surprise with its own blast radius) or using the import wizard every time. The zero-config fix is re-delimiting the file itself, here, in seconds.
Good to know
- European-style numbers (1.234,56) are data, not delimiters — re-delimiting doesn’t rewrite decimal commas inside fields; normalize those with find & replace if the destination needs dot-decimals.
- Going TO semicolon for a European recipient’s Excel? Also tick the UTF-8 BOM option so their accents render.
- Pipe (|) is the pragmatic choice when your data is full of both commas and tabs — rare in the wild, ugly, effective.
Frequently asked questions
Why not just find-and-replace semicolons with commas?
Because data containing the new delimiter breaks: “Acme, Inc.” with naive replacement becomes two columns, and existing quoted fields can end up double-mangled. Parsing then re-serializing — what this tool does — is the only transformation that’s correct for arbitrary data.
How do I know what delimiter my file uses now?
Drop it here — the sniffer reports what it detected (visible in the toolbar), and the grid proves it: correct columns mean correct delimiter. A file that renders as one wide column was sniffed wrong or is genuinely delimited by something exotic; override in the toolbar.
Excel still opens my comma CSV as one column — why?
Your Windows locale’s list separator is probably a semicolon, so Excel expects semicolons in double-clicked CSVs. Import via Data → From Text/CSV (which asks about the delimiter), or convert the file to semicolons here so double-click just works on that machine.