Add line numbers
ClientPrefix or suffix line numbers on pasted text—reorder with sort lines first if needed.
About Add line numbers
Prefix or suffix line numbers on pasted code or logs—custom start index, browser-only. The interactive transform on this page runs in your browser tab—Toolcore does not need your paste for the core operation described above.
How to use this page
Paste or type in the main workspace, run the primary action from the toolbar, then copy or download the result. Use Load example when the page offers it, or URL prefill (?q= / ?qb=) so agents and tickets open the same input.
Nearby workflows on Toolcore
- Sort lines alphabetically — Locale-aware A→Z / Z→A line sorts plus reverse—optional trim or case folding, browser-only. for the next text or markup step in your edit loop.
- Plain text diff — Compare two text drafts side by side—unified view, sample pre-filled, client-side. for the next text or markup step in your edit loop.
- List converter — Convert lines ↔ JSON array ↔ CSV row—paste lists for configs, APIs, or spreadsheets; local only. for the next text or markup step in your edit loop.
- Remove duplicate lines — Collapse repeated lines in pasted text—trim or case-fold keys, optional sort—browser-only deduper. for the next text or markup step in your edit loop.
Common use cases
- Prepare code snippets for docs or tickets with stable line references.
- Add row numbers to CSV-like paste before sorting or deduping elsewhere.
- Format log excerpts for review meetings.
Common mistakes to avoid
Numbering blank trailing lines you meant to drop
Empty lines still receive numbers—trim content first if needed.
Assuming IDE gutter sync
Output is plain text; re-import into an editor if you need fold markers.
FAQ
Can I start at zero?
The start index must be at least 1 on this page.
Does this sort lines?
No—use sort lines before or after numbering as needed.
Common search terms
Phrases people search for that match this tool. See the full long-tail keyword index.
- add line numbers to text online
- number lines in code snippet browser
- prefix line numbers log paste
- line numbering tool for text
More tools
Related utilities you can open in another tab—mostly client-side.
Sort lines alphabetically
ClientLocale-aware A→Z / Z→A line sorts plus reverse—optional trim or case folding, browser-only.
Plain text diff
ClientCompare two text drafts side by side—unified view, sample pre-filled, client-side.
List converter
ClientConvert lines ↔ JSON array ↔ CSV row—paste lists for configs, APIs, or spreadsheets; local only.
Remove duplicate lines
ClientCollapse repeated lines in pasted text—trim or case-fold keys, optional sort—browser-only deduper.