Spreadsheet Tools

CSV Joiner

Paste or load two delimited tables, choose the key column on each side, preview matched rows, and export the joined CSV locally.

Join two CSV tables by key

Choose a key column on each table. Duplicate key values can produce multiple output rows, just as they do in a relational join. Right-side name collisions are renamed instead of silently overwriting left columns.

Left CSV

Right CSV

Left key

Right key

Join type

ReadyBoth tables are parsed and joined in this browser tab.

CSV and spreadsheet boundaries

CSV has no universal schema or type system. Delimiter detection and type summaries are practical heuristics, while repairs create a new copy instead of silently altering the source. Excel conversion focuses on cell values and simple worksheets rather than promising perfect preservation of formulas, macros, charts, external links, formatting or every workbook feature.