Line Number Adder
Text & Code · Free Online Tool
Add line number prefixes to each line.
Custom Sequence
Set the starting number and step to generate any ascending or descending sequence.
Separator & Padding
Choose a separator style and optionally zero-pad numbers for aligned columns.
Live & Copyable
Numbering updates instantly as you type, with one-click copy to clipboard.
How to Use Line Number Adder
- 1Enter or paste your text or code into the input area.
- 2Choose the desired operation (format, convert, analyze, etc.).
- 3Click the action button to process.
- 4Copy the result from the output area.
Features
- ✓100% free — no signup, no subscription, no ads
- ✓Runs entirely in your browser — data never leaves your device
- ✓Fast and lightweight — instant results
- ✓Cross-platform — works on desktop, tablet, and mobile
Frequently Asked Questions
Can I format code in different styles?
Yes, the SQL Formatter and other code tools support multiple formatting options and indentation styles.
Is regex testing case-sensitive?
The Regex Tester supports case-sensitive and case-insensitive matching, along with global and multiline flags.
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Learn the concept
Learn the concept
Understand the programming ideas behind this tool.