What does Number Lines do that other Text pages on this site do not?

Start index, optional zero-pad, and custom separator after the number. Short version: Add line numbers with pad and separator options.

Does Number Lines upload my file or text to Tool-You servers?

No. Number Lines runs in this browser tab. Files stay on the device. Limit note: Start 0–100000. Pad 0–8. Custom separator. Max 200,000 characters.

Should I use Prefix and Suffix Lines instead of Number Lines?

Use Number Lines when you need Add line numbers with pad and separator options. Use Prefix and Suffix Lines when you need Add prefix/suffix per line; skip empties optional. They share a category (Text) but not the same job.

What are the limits of Number Lines?

Start 0–100000. Pad 0–8. Custom separator. Max 200,000 characters. Also: Start index, optional zero-pad, and custom separator after the number.

Number Lines

Add line numbers with pad and separator options.

Start index, optional zero-pad, and custom separator after the number.

What Number Lines does

Start index, optional zero-pad, and custom separator after the number.

The interactive controls for Number Lines load after this article so crawlers still read the instructions. Path /number-lines is the canonical address. Work happens on this device; Tool-You does not take a copy of the file or pasted text for Number Lines.

How to use Number Lines

Keep this tab on Number Lines (/number-lines). Pasting into the wrong Text tool (for example Prefix and Suffix Lines) changes the job.
Paste or type the input Number Lines expects. Path hint: number lines. Add line numbers with pad and separator options.
Apply the Number Lines action only. Sort Lines is a different transform (Sort lines A–Z, Z–A, or as numbers.). Start index, optional zero-pad, and custom separator after the number.
Copy the output of Number Lines if you need it elsewhere. Size/complexity still follows: Start 0–100000. Pad 0–8. Custom separator. Max 200,000 characters.
If the text job is actually Add prefix/suffix per line; skip empties optional., leave Number Lines and open Prefix and Suffix Lines.

When not to use Number Lines

Skip Number Lines when a neighbor tool matches better — start with Prefix and Suffix Lines or Sort Lines — or when the description already warns the job will fail. In the tool’s own words: Start index, optional zero-pad, and custom separator after the number.

Questions about Number Lines

What does Number Lines do that other Text pages on this site do not?: Start index, optional zero-pad, and custom separator after the number. Short version: Add line numbers with pad and separator options.
Does Number Lines upload my file or text to Tool-You servers?: No. Number Lines runs in this browser tab. Files stay on the device. Limit note: Start 0–100000. Pad 0–8. Custom separator. Max 200,000 characters.
Should I use Prefix and Suffix Lines instead of Number Lines?: Use Number Lines when you need Add line numbers with pad and separator options. Use Prefix and Suffix Lines when you need Add prefix/suffix per line; skip empties optional. They share a category (Text) but not the same job.
What are the limits of Number Lines?: Start 0–100000. Pad 0–8. Custom separator. Max 200,000 characters. Also: Start index, optional zero-pad, and custom separator after the number.