Line Number Tool

Add, remove, or renumber sequential line numbers on a list of text. Add prepends 1. , 2. … with a chosen start, step, and separator. Remove strips a leading number-and-separator from each line (recognizing ., ), :, space, and tab styles). Renumber keeps each line's existing separator style but re-sequences the numbers from a chosen start, filling gaps. Everything runs locally in your browser.

Input — one line per row

Output

Start at

Step

Separator

Aggressive (strip "1." even without a space)

Start at

Step

Enter some lines to see results.

Add joins each line with n <separator> line; the separator is whatever you type (e.g. ". ", ") ", a tab, " | "). Remove detects a leading number followed by one of . ) : space or tab — but only when followed by whitespace (so 1.5 is left alone); turn on Aggressive to strip the punctuation regardless. Renumber reads the separator style from the first numbered line and rewrites all numbers, adding numbers to any un-numbered lines using that style. Runs locally — nothing leaves your browser.