How to use the Line Numbering Tool
1. Paste multi-line text into the left panel.
2. Optionally adjust the starting number and the separator between the number and the line.
3. Copy the numbered output for use in documents, code review notes, or instructions.
What is it?
Adding line numbers to text is useful for creating numbered lists, step-by-step instructions, referencing specific lines in code reviews, or annotating log files. Instead of manually numbering each line, this tool does it instantly for any number of lines.
The configurable separator lets you match different formatting conventions: "1. " for ordered lists, "1: " for log annotations, "1\t" for tab-separated output. The starting number can be set to any value — useful when numbering continues from a previous section.
Example
Install the package Configure the settings Run the server
1. Install the package 2. Configure the settings 3. Run the server
Useful for numbered instructions, step guides, log annotations, and code review comments.
Benefits
Add line numbers to code examples in documentation
Numbered lines let readers reference specific lines in explanations, tutorials, and code reviews without ambiguity.
Reference exact lines in bug reports and code reviews
'See line 42' is only useful when the reader can see line numbers — add them to any code block before sharing.
Number diff output for precise before/after comparison
Adding line numbers to both versions of a file makes mapping changes between them straightforward.
Prepare text for scripts and tools that require numbered input
Some analysis pipelines, diff tools, and log processors expect line-numbered input — generate it instantly.
Frequently asked questions
Can I start numbering from a number other than 1?
Yes — set the Start at field to any number, including 0 or negative numbers. This is useful when your numbered content continues from a previous section or you need zero-indexed numbering.
What separators work well?
Common separators: '. ' (1. item), ': ' (1: item), ') ' (1) item), '. ' (numbered then tabbed). The separator field accepts any text including spaces and tabs.
Does this preserve blank lines?
Yes — blank lines in the input are preserved and also receive line numbers. If you want to skip numbering blank lines, clean the text first using the Text Cleaner tool with 'Remove empty lines' enabled.