Add Line Numbers — Browser Text Tool

Text

Add Line Numbers is a browser text tool that prefixes each line with a line number.

Add Line Numbers

Runs in this browserInput and recent results are processed only in this browser tab. They are not sent to or stored on a server.

This list stays only in current-tab memory and is cleared on reset.

Text

ResultRule

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Each line receives a one-based number with the selected separator.

What is it

Add Line Numbers lets you paste text, transform or analyze it, and read the result immediately. It is useful for editing, cleanup, and repeatable text preparation without server storage.

result = lines(input).map((line, index) => `${index + 1}. ${line}`)

How to use

1Paste or type text.
2Choose an option if available.
3Read the transformed result.

Reference

Add Line Numbers — Browser Text Tool Reference
Input	Result
Hello World	prefixes each line with a line number

Sources & standards

MDN Web Docs: Client-side web APIs - MDN Web Docs

FAQ

Is Add Line Numbers input sent to a server?

No. This tool runs in your browser and does not send input to a server.

Can I use Add Line Numbers on mobile?

Yes. It works on mobile and desktop browsers that support text input.