TSV to CSV
Convert TSV to CSV. Paste TSV on the left; the CSV output builds on the right as you type.
A tab-separated file with a header row and a few data rows converts to the same header and rows joined by commas instead of tabs, with quoting reapplied wherever a cell needs it under CSV’s rules. Both formats share one tabular codec internally, so the row data itself never changes, only the character between fields.
Quoting differs by delimiter
TSV quotes a cell when it contains a literal tab, a double quote, or a line break. CSV quotes for the same three reasons but checks for a comma instead of a tab. A cell like "Boston, MA" needs quotes once it’s CSV, because of the comma, even if the same cell in the TSV source didn’t need quoting at all.
Header and no-header files
With Header row on, the default, the first line’s cells become each row’s keys internally before the CSV output is built with the same names. Turn it off for a TSV export with no header line, and rows convert as plain arrays; the resulting CSV also has no header row.
Coming back the other way
To go from comma-separated back to tab-separated, use the CSV to TSV converter; both directions run through the exact same parser and serializer.