CSV Insert Column
Add a new column to a CSV at a chosen position, filled with a constant value. Runs entirely in your browser, no upload.
CSV insert column
Add a new column to a CSV, filled with a constant value, at any position. For
example, append a source = import column, or insert an id column at the front.
It runs in your browser; nothing is uploaded.
Options
- New column name — the header for the column (used when first row is a header is on).
- Fill value — the constant written into every data row.
- Position — a 1-based index, or
endto append. Clamped to the row width. - Delimiter — comma, tab, semicolon, pipe, or any single character.
FAQ
What happens if the position is larger than the number of columns?
It's clamped: asking for position 10 on a 3-column CSV simply appends the new column at the end (same as end). Position is 1-based, so 1 inserts at the very front.
What if my rows have different lengths?
Ragged CSVs are accepted — rows aren't forced to a uniform width. The insert position is clamped per row, so a short row still gets the new value at its own end rather than causing an error.
How do I use a tab or semicolon as the separator?
Type the word tab, comma, semicolon, or pipe in the delimiter field — or any single character (e.g. ;). Multi-character delimiters other than those names are rejected. The output uses the same delimiter as the input.
Is my data uploaded?
No — it's processed locally with WebAssembly.
Want per-row computed values instead of a constant?
Use the CSV formula tool.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool csv-insert-column "a,b
1,2
3,4" 'name=source'New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/csv-insert-column/?data=a%2Cb%0A1%2C2%0A3%2C4&name=source&value=import&position=end&header=true&delimiter=%2CMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.