Text tool
Line Numberer
Number pasted lines or remove numbers previously added by this tool.
Output
How the line numberer works
Add or remove line numbers with a chosen starting value and separator.
Starting at 3 with '. ' turns Alpha and Beta into '3. Alpha' and '4. Beta'.
Assumptions and limitations
Removal only strips a leading integer followed by the selected separator, preserving all other text.
Inputs and results stay in your browser. Blank, invalid, or mathematically undefined inputs show a clean placeholder instead of a broken number.
Practical use
Use this text tool to explore scenarios quickly, then verify important decisions against the original source data or requirements.
Frequently asked questions
Does the line numberer send my data anywhere?
No. It runs client-side in your browser and makes no network requests.
Why is the result blank or shown as a dash?
One or more inputs are blank, outside the accepted range, or would make the calculation undefined. Check the labels and enter finite values.
Can I use decimal values?
Yes, where decimals are meaningful. Counts that represent whole items may require integers.