Add a Column to CSV, free in your browser

Append a named column to a CSV or TSV file and fill each data row with the same value.

How to add a column to CSV

1. Choose a CSV or TSV file.
2. Enter the new column name and the value to repeat in each row.
3. Preview and download the updated CSV.

Limits & good to know

• CSV and TSV files up to 50 MB are processed on your device.
• The new column name must be different from existing names.
• The new column is appended after existing columns.

Frequently asked questions

Are my files uploaded to a server?

Your files are processed on your device, not uploaded to our servers. Your file and edits are saved in this browser for recovery, and previous documents remain in Saved drafts when you open another file. Use Saved drafts to resume or delete individual copies, or clear this site’s browser data to remove all copies. Browser storage can be cleared or become unavailable; download important work.

Can each row have a different value?

This tool fills every row with one value. For row-specific values, edit the CSV in a spreadsheet app.

Is this really free, or free "until you hit a limit"?

Really free. Unlike most "free" PDF sites there is no task-per-day cap, no locked Pro features, no watermark stamped on your file, and no payment step before download. Every tool is the full tool.