Number Lines Tool

About this calculator

This tool adds a sequential line number as a prefix to every line of a block of text, turning an unnumbered list or block of text into one where each line's position is immediately visible, without manually counting or typing numbers one by one. It preserves the original line order and content, simply prepending the count.

It is used by developers and writers who need to reference specific lines when discussing a piece of text, a config file, or a code snippet — saying "see line 14" only works if the lines are actually numbered. It's also handy for numbering steps in an instruction list, items in a to-do list, or entries in any plain-text list pasted from somewhere that stripped the original numbering.