Add Line Numbers | Custom Formatting & Zero-Padding
Add sequential line numbers to every line with built-in formats (1., [1], (1), 1:) or a custom prefix/suffix. Choose the start number, set zero-padding width, and align output for code, documents, and lists—processed locally in your browser.
How to Use This Tool
- 1
Paste your text; each line will be numbered
- 2
Pick a format: 1., [1], (1), 1:, or Custom
- 3
Set the start number and optional zero-padding width
- 4
Use Live mode or click “Add Numbers” to process
- 5
Copy the numbered output for docs, code, or lists
Use Cases & Examples
Code Documentation & Snippet References
Add line numbers to code blocks for tutorials, reviews, and file line matching.
Document Indexing & Cross-Referencing
Number lines for citations, footnotes, and cross-references in manuscripts.
Numbered Lists & Outline Creation
Turn plain text into numbered lists and outlines in seconds.
Teaching Materials & Exercise Sets
Number questions, steps, or exercises for worksheets and lessons.
What Is Line Numbering?
Input text is split by line breaks; an incrementing counter is prefixed using your chosen start value.
Built-in formats (1., [1], (1), 1:) and custom prefix/suffix are supported, plus fixed-width zero-padding.
Runtime is linear to input size, so thousands of lines process instantly in modern browsers.
Frequently Asked Questions
Q.Can I start numbering from a different number instead of 1?
A. Yes—set any start value to continue an existing sequence or use zero-based numbering.
Q.Can I customize the format like brackets or parentheses?
A. Yes—use built-ins (1., [1], (1), 1:) or define custom prefix/suffix for full control.
Q.Does it support zero-padding for aligned numbers?
A. Yes—enable zero-padding and set a width (e.g., 001, 010) for aligned numbers in monospaced text.
Q.What happens to empty lines? Are they numbered?
A. By default, empty lines are counted and numbered; every line is treated as an item.
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