Combine Columns in CSV Files Online
Combine multiple columns into one in CSV files directly in your browser. Merge first name and last name, join address fields, or concatenate any columns with a custom separator — no upload required.
How to combine Columns in CSV files
- Drop your file onto the upload area. The first two columns are ticked by default and the output name is set to both names joined by an underscore.
- Tick the columns to combine in the order you want them joined. Each ticked column shows its position (#1, #2, and so on), and the order follows your clicks, not the file's column order.
- Type the separator, such as a space, ", " or " - ", and set the output column name.
- Tick Remove source columns if you only want the combined column, then click Combine Columns.
- Check the preview and download the file in the same format.
Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.
Worked example
An international order export stores the delivery address across four columns. The courier's upload form wants one address line per parcel.
Input (CSV)
recipient,street,city,postcode,country
Priya Shah,12 Cuba Street,Wellington,6011,New Zealand
Tom Walsh,8 Quay Road,Cork,,Ireland
Ines Duarte,Rua Augusta 40,Lisboa,1100-048,PortugalSettings
- Columns, in click order: street, city, postcode, country
- Separator: ", "
- Output column name: full_address
- Remove source columns: ticked
Result
| recipient | full_address |
|---|---|
| Priya Shah | 12 Cuba Street, Wellington, 6011, New Zealand |
| Tom Walsh | 8 Quay Road, Cork, Ireland |
| Ines Duarte | Rua Augusta 40, Lisboa, 1100-048, Portugal |
Values are joined in the order the columns were ticked, with the separator between them. Tom's postcode is empty, and it is skipped along with its separator, so there is no ", ," gap. With the source columns removed, full_address takes the position of the last source column. Unticked columns such as recipient stay where they were.
Working with CSV files
Every column is turned into text before joining, using the type it was given when the CSV loaded. A column of whole numbers joins as 6011. A column with decimals joins in its shortest form, so 249.50 in the file becomes 249.5 in the combined value. A whole value such as 1200 in a decimal column joins as 1200.0. If exact formatting matters, as with prices or codes, clean the source column first or join the raw text in the SQL workspace.
Empty CSV fields load as NULL and are skipped, so no doubled separator appears. A field containing only spaces is not empty, though. It is joined as-is and leaves a visible gap, so trim first. If your separator contains a comma, for example ", ", the combined values are quoted in the downloaded CSV. Any tool that reads the file correctly will still see one column, but a naive split on commas will not.
Frequently Asked Questions
Why does combining CSV columns change 249.50 to 249.5?
The column was read as a number, and numbers are converted to text in their shortest form when joined. If the trailing zero matters, build the value in the SQL workspace with a format function such as printf('%.2f', price).
Will a comma separator break my CSV?
No. Values containing a comma are wrapped in double quotes when the CSV is written, so the combined column stays one field.
What happens to empty (null) values when combining columns?
They are skipped, and so is the separator next to them. Combining "Cork", null and "Ireland" with ", " gives "Cork, Ireland". Empty strings are not null, so they are joined as-is.
Can I combine more than two columns, and control the order?
Yes. Tick as many columns as you need. They are joined in the order you tick them, shown as #1, #2 and so on next to each column name.
Can I leave the separator empty?
Yes. With an empty separator the values are joined directly, for example "AB" and "123" become "AB123".
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