Add Line Numbers
Add sequential line numbers to each line of text (1., 2., 3., …) without changing the original content.
Input
Output
Tip: You can verify in DevTools → Network that nothing is uploaded.
About this Add Line Numbers
Add Line Numbers prefixes each line with an incrementing number so you can reference specific lines during reviews, debugging, or discussions.
This is useful for code snippets, logs, transcripts, and long lists. Line content and order are preserved — only the numbering prefix is added.
- Process text data quickly without external tools
- Transform content for development workflows
- Clean and format text for analysis
- Enable Auto to transform as you type
- Upload text files directly from your device
- Download the result when done
FAQ
No. Everything runs locally in your browser. Nothing you paste is sent to a server.
After the page loads once, it will typically keep working offline (unless you hard refresh with no cache).
No. Your input stays in your browser. Only optional preferences like theme or language may be stored.
Any plain text. You can paste text directly into the input box.
No. It only adds a line number prefix; the rest of each line remains unchanged.
Yes. Empty lines are counted and numbered so line references remain consistent.
If your tool has a start option, you can change it. Otherwise numbering typically starts at 1.