Line Number Adder

The Line Number Adder is a browser-based utility for adding line numbers to any text or stripping existing line numbers.

Sharing code with line numbers makes code reviews more efficient, and numbered log files let you quickly reference specific entries. In document proofreading, line numbers make correction instructions precise and unambiguous.

You can set any start number, choose a separator (dot, colon, tab, or space), apply zero-padding or space-padding, and optionally skip empty lines for a clean result. The custom format feature lets you use %n as a placeholder to generate complex patterns like "(1) " or "[Line 1]: " with ease.

All processing happens entirely in your browser — no text is ever sent to a server.