Add Line Numbers

What this tool does

Add Line Numbers prefixes each line with a counter you control: where it starts, how much it increases, how numbers are aligned and what separates them from the text. It can also strip numbers that are already there, so you can renumber a list after editing it.

Numbered lines make text easier to discuss: “see line 14” is quicker than quoting a sentence, legal drafts and transcripts are referenced by line, and recipes or instructions read better as numbered steps. Adding numbers by hand is slow and breaks the moment you insert a line in the middle.

This tool counts lines exactly as they appear, splitting on any line ending, and builds each label from your settings: start value, increment (negative steps count down), and style, either decimal, upper or lower Roman numerals (valid from 1 to 3999) or spreadsheet-style letters where 27 becomes “aa”. Zero padding uses the width of the largest number, so 1 to 120 runs from 001 to 120. Blank lines can be skipped so paragraphs do not consume numbers. Text never leaves your browser.

How to use Add Line Numbers

1. Paste the text you want to number, or click Sample for a short recipe.
2. Keep Action on “Add line numbers”, or switch to “Remove existing line numbers” to clean a numbered list.
3. Choose the Number style, then set “Start at” and “Increment”.
4. Pick the “Separator after the number”, such as “1. text”, “1) text” or a tab, or enter a custom one.
5. Add “Text before the number” if you want labels like “Step 1.”, and choose an alignment under “Align numbers”.
6. Decide whether empty lines are numbered, then copy or download the output.

Tips for better results

• Use a tab separator and leading zeros when pasting into a spreadsheet, so the numbers land in their own sorted column.
• Start at 10 with an increment of 10 to leave room for inserting lines later, a habit borrowed from BASIC programs.
• Right-aligning with spaces keeps the text column straight in monospaced fonts when numbers pass 9 or 99.
• To renumber an edited list, run it through Remove first and then Add again.

Common use cases

• Numbering lines of a contract or transcript so reviewers can cite them.
• Turning a plain list of instructions into numbered steps for a manual.
• Adding line numbers to a code snippet in an email or document that has no syntax highlighter.
• Creating outline labels such as i, ii, iii for a report appendix.

Common mistakes to avoid

• Expecting Roman numerals for 4000 and above; standard notation stops at 3999, so larger values are shown as digits.
• Leaving empty lines numbered in prose, which makes numbers jump between paragraphs.
• Using the remove action on text where lines genuinely start with a number, such as years or quantities followed by a dot.