Auto Numbering Tool
Add sequential numbers to CSV rows or a list of text lines — set the start value, step, prefix, and zero-padding exactly how you want it.
How to use Auto Numbering Tool
- Start by providing the required input: Drop a CSV file.
- Set the inputs and options shown here: Column name, Start, Step, Prefix, Zero-pad to width.
- Run the tool with Add Numbers.
- Review the results, then choose an output control: Download.
Adding sequential numbers without an Excel formula
Numbering a list of items — rows in a CSV, lines in a plain list — is a one-line formula in a spreadsheet, but configuring padding, a custom prefix, or a non-standard start value takes more fiddling than it should. Setting those options directly and applying them in one click is faster for a one-off task.
Why zero-padding matters for sorting
Item-1, Item-2, Item-10 sorts alphabetically as 1, 10, 2 — wrong order. Zero-padding to a consistent width (Item-01, Item-02, Item-10) makes alphabetical and numerical sort order match, which matters when the numbered list will later be sorted by filename or string comparison.
Can I start numbering from something other than 1?
Yes — set any start value, useful for continuing a sequence from a previous batch.
Does this work on both CSV data and plain text lists?
Yes — switch between CSV column mode and text line mode depending on what you're numbering.
Need numbering that restarts within groups?
Use Row Numbering instead, which supports restarting the count whenever a chosen column's value changes.