About the Add Line Numbers
The Add Line Numbers tool is a free, browser-based utility that instantly prepends sequential numbers to each line of your text without requiring login or uploading to servers. It processes entirely in your browser for complete privacy and works with any text content—from code snippets and logs to poetry and lyrics. The tool offers customizable formatting options, allowing you to choose numbering styles, skip empty lines, or add custom prefixes and suffixes to suit your exact needs.
How Add Line Numbers works
How to use it
- Type or paste your text in the box above.
- A number is added to the start of every line instantly.
- Copy the numbered text with one click.
How it works
The tool splits your text on line breaks and prefixes each line with its sequential number, padded so the numbers line up. It is handy for referencing items in a list, lines of code or steps.
Common uses
- Debugging code by referencing specific line numbers in error reports or test failures
- Numbering documentation, instructions, or procedures for clear step-by-step referencing
- Adding numbers to song lyrics, poetry, or scripts for easier discussion and annotation
- Preparing text logs or data files for analysis where line position matters
- Creating numbered lists with consistent formatting for legal documents, contracts, or formal requirements
- Testing applications that validate user input on a line-by-line basis
Frequently asked questions
Is my data secure and private?
Yes. Everything runs entirely in your browser—no text is uploaded to any server or stored anywhere. Your data never leaves your device.
Do I need to create an account or pay?
No. The tool is completely free to use with no registration, login, or payment required. Use it as many times as you need.
Can I customize the numbering format?
Yes. You can choose from preset formats like '1.', '1)', or '[1]', or create your own custom format by using %n as a placeholder for the line number.
What happens with empty lines?
By default, empty lines and whitespace-only lines are still numbered. You can enable an option to skip them if you prefer to number only lines with content.
How fast is it?
The tool processes instantly as you type or paste. Results appear immediately with no waiting or processing delays.
What file types can I use?
The tool works with plain text only. Paste any text content—code, logs, lyrics, documents—and get numbered output instantly.