Row Numbering Tool
Add a row-number column to your CSV — optionally restarting the count every time a chosen grouping column changes value.
How to use Row Numbering Tool
- Start by providing the required input: Drop a CSV file.
- Set the inputs and options shown here: Restart numbering when this column changes:.
- Run the tool with Add Row Numbers.
- Review the results, then choose an output control: Download CSV.
Numbering that resets per group, not just straight through
A report broken into sections often needs each section numbered independently — item 1, 2, 3 within "Region: North," then restarting at 1 for "Region: South" — rather than one continuous count through the whole file. Restarting the count whenever a chosen column's value changes produces exactly that.
Straight-through versus grouped numbering
Leave grouped numbering off for a simple continuous row index; turn it on and pick a grouping column when your data has a natural category structure that the numbering should respect.
Does the data need to be sorted by the grouping column first?
Yes — grouped numbering restarts whenever the grouping column's value changes between consecutive rows, so your data should already be sorted by that column for the grouping to make sense.
What column gets added — a new one, or does it replace existing data?
A brand new "#" column is added as the first column; nothing in your existing data is altered.
Need custom prefixes or padding instead of plain numbers?
Use Auto Numbering Tool instead for prefix, padding, and step configuration.