Add Line Numbers

The Add Line Numbers tool prefixes every line of your text with a running sequential number. It is useful for creating numbered lists, referencing lines in code reviews or documentation, preparing legal or transcript line references, and turning a plain list into an ordered one — all without a spreadsheet or text editor macro.

How it works

The tool splits your input on newlines and walks through it line by line, attaching a counter that increments with each numbered line. You control four options:

• Start at — the first number, which can be 0, 1, or any positive or negative integer.
• Separator — the characters placed between the number and the line text (e.g. ”. ”, ”: ”, ” | ”).
• Zero padding — pads every number to the same width, calculated from the largest number that will actually be emitted so they align in a column.
• Skip blank lines — leaves empty lines unnumbered while preserving their position.

Example

Numbering three lines starting at 1 with the ”. ” separator turns:

first line
second line
third line

into:

1. first line
2. second line
3. third line

With zero padding and 100+ lines, line 7 would render as 007. ... so every number lines up.

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