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// about this tool

Add Line Numbers Online

Updated 2026-08-19

Add line numbers to text online for free. Paste any text and SnapTools prefixes each line with a sequential number and the separator you choose — instantly, in your browser. Nothing is uploaded.

Numbering lines by hand is tedious and breaks the moment you insert a line. This tool renumbers the whole block in one step, with a configurable starting number for snippets that continue from elsewhere and a choice of separator to match your style — a dot for a list, a colon for references, a tab for data. Copy the result straight into documentation, steps, or a checklist.

// how to use

  1. 1 Paste your text into the input panel on the left.
  2. 2 Choose a starting number and the separator between the number and each line.
  3. 3 Read the numbered text on the right, then copy or download it.

// examples

Number each line
Input
first
second
third
Output
1. first
2. second
3. third
Custom separator
Input
alpha
beta
Output
1: alpha
2: beta

// common uses

Numbering a list or set of steps Referring to specific lines when reviewing text Preparing numbered output for documentation Creating ordered checklists from plain lines

// faq

Is my text uploaded to a server?
No. Numbering runs entirely in your browser, so your text never leaves your machine.
Can I change the starting number?
Yes. Line numbers usually start at 1, but you can begin from any number — useful when a snippet continues from a larger file.
Can I choose the separator?
Yes. Pick what goes between the number and the line — a dot and space, a colon, a parenthesis, or a tab — to match the style you need.
Are blank lines numbered too?
Every line is numbered in sequence, including blank ones, so the numbering stays aligned with the original line positions.
How do I remove line numbers later?
To strip a leading number pattern, use the Find & Replace tool with a regular expression that matches the prefix you added.

// works with your data

Sort & Dedupe Lines Slug Generator Reverse Text Text Repeater Remove Duplicate Lines Whitespace Remover

Use this via API

Get a free API key → 
curl -X POST https://thesnaptools.com/api/v1/tools/add-line-numbers \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text":"first second third"}'