CSV Delimiter Converter
How it works
CSV files use a delimiter character to separate field values within each row. Despite the "C" in CSV standing for "Comma," real-world files use a variety of delimiters: tabs (TSV), pipes (|), semicolons (;, common in European locales where commas are used as decimal separators), and colons. Delimiter mismatch is a frequent source of import failures.
**Why delimiter variation exists** European CSV exports use semicolons because the comma is the decimal separator in many European number formats (1.234,56 rather than 1,234.56 — a semicolon-separated file with a value of 1.234,56 would break if comma-delimited). Tab-separated values (TSV) are preferred when field values may contain commas (e.g., address fields, free-text descriptions). Pipe delimiters are common in legacy mainframe and EDI exports where tabs and commas appear in data.
**Quoting and escaping** When converting to a new delimiter, values that contain the new delimiter must be quoted with double quotes per RFC 4180. Values already containing double quotes must have those quotes escaped by doubling them ("he said ""hello"" " is the escaped form of: he said "hello"). This tool handles quoting automatically — it parses the source with its delimiter and re-serializes with the target delimiter, applying quoting rules correctly.
**Multi-character and fixed-width** Some systems export fixed-width files or use multi-character delimiters (e.g., " | " with spaces). The conversion tool normalizes these to single-character standard delimiters for maximum compatibility with downstream tools.
Frequently Asked Questions
- In many European countries (Germany, France, Italy, the Netherlands), the comma is used as the decimal separator in numbers (1.234,56 means one thousand two hundred thirty-four point fifty-six). If commas were used as CSV delimiters, a number like 1.234,56 would be split into two fields. Semicolons are used as delimiters instead to avoid ambiguity. This is controlled by the regional 'list separator' setting in Windows and Excel.
- Values containing the target delimiter are automatically quoted with double quotes per RFC 4180. For example, converting to comma-separated: if a value is 'New York, NY', it becomes '"New York, NY"' in the output. Values already containing double quotes have the quotes doubled: '5" screen' becomes '"5"" screen"'. This is handled automatically by re-parsing with the source delimiter and re-serializing with the target delimiter.
- TSV (Tab-Separated Values) uses tab characters as delimiters. TSV is preferred when field values frequently contain commas (addresses, descriptions, notes) — since tabs rarely appear in natural text, TSV usually requires no quoting. However, tabs do appear in code samples and certain data types. CSV is more universally supported by APIs, databases, and spreadsheets. For data with commas in values, TSV is cleaner; for maximum compatibility, CSV with proper quoting is preferred.
- Fixed-width format (no delimiter — columns are positionally defined by character offsets) is a different paradigm from delimited formats. Converting fixed-width to CSV requires knowing the column start positions and widths (e.g., columns at positions 0–9, 10–24, 25–39). This tool handles delimiter-to-delimiter conversion. For fixed-width conversion, use Python's pandas.read_fwf(), the unix cut command with -c flag, or awk with substr().