What can I do with Number Lines?

Add sequential numbers to each line. Number Lines is part of the Text shelf on utils.sbs and is designed for quick, one-off tasks.

Is Number Lines free to use?

Yes. Number Lines is free, requires no account, and has no per-file or per-use charge.

Are my files uploaded when I use Number Lines?

No. Number Lines is designed to process your input locally in the browser. Files are not uploaded to a server for processing.

What formats does Number Lines support?

It works with plain text, code, markup and structured text, and returns a downloadable text file.

Can I use Number Lines on my phone?

Yes. Number Lines is responsive and works in modern mobile browsers. Very large files may be limited by the device's available memory.

Text tool

Number Lines

Add sequential numbers to each line.

Runs on-deviceNo sign-upFree

All text tools

Workspace

Number Lines

Runs locally

Start at

Input

335 chars · 63 wordsStays in this tab

Output

The guide

By the utils.sbs team · Reviewed November 2026 · How we build and review tools

Quick answer

Number Lines is a free browser-based text tool. Add sequential numbers to each line. It runs with JavaScript locally, requires no account and does not upload your files. Open the page, add your input, adjust any options and download the result.

What is Number Lines?

Number Lines is a free browser-based text tool from utils.sbs. Add sequential numbers to each line. It is built for quick, focused jobs: open the page, add your input, adjust the options and take the result with you. No account, install or server upload is required.

At a glance

Category	Text
Input	Plain text, code, markup or JSON
Output	A downloadable text or code file
Engine	JavaScript
Processing	In your browser
Price	Free
Account	Not required

How Number Lines works

Text is processed in the browser with JavaScript and downloaded from a local blob. Nothing is uploaded.

How to use Number Lines

1Open Number Lines and add your input.
2Use the default settings, or choose the format or detail level that matches your goal.
3Run the tool, check the preview or result, and download the output.

When to use Number Lines

Clean, transform or compare text before using it elsewhere.
Convert markup, JSON or structured text between formats.
Count, format or inspect content quickly in the browser.

Limitations

Very large inputs may be limited by the browser's available memory.

Privacy and accuracy

Number Lines processes its input in the browser whenever the platform API allows it. Files and values are not uploaded to a server for processing, and the tool does not require an account. For calculations, use the result as a reference and verify important decisions against the source formula or a qualified professional. Read our methodology.

FAQ

Number Lines questions

What can I do with Number Lines?
Add sequential numbers to each line. Number Lines is part of the Text shelf on utils.sbs and is designed for quick, one-off tasks.
Is Number Lines free to use?
Yes. Number Lines is free, requires no account, and has no per-file or per-use charge.
Are my files uploaded when I use Number Lines?
No. Number Lines is designed to process your input locally in the browser. Files are not uploaded to a server for processing.
What formats does Number Lines support?
It works with plain text, code, markup and structured text, and returns a downloadable text file.
Can I use Number Lines on my phone?
Yes. Number Lines is responsive and works in modern mobile browsers. Very large files may be limited by the device's available memory.

Keep going

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