Line Number Adder

How to use

1. Paste text — Enter multiline text
2. Configure — Set start number, separator, and padding
3. Copy — Copy the numbered text

What Is a Line Number Adder?

A line number adder prefixes each line of text with a sequential number, producing output that is easy to reference, cite, or quote. While most code editors render line numbers visually in the gutter, those numbers are not part of the file content — copying the text loses them. This tool actually inserts the numbers into the text itself, so they survive copy-paste, email, PDF export, and chat messages.

Configuration Options

• Starting number: Begin at 1, 0, or any custom value — useful when continuing from another excerpt
• Separator: Choose period (1.), colon (1:), bracket ([1]), tab, or any custom character between number and text
• Zero padding: Pad numbers to a fixed width (001, 002) so they align in monospace fonts
• Skip blank lines: Optionally don't number empty lines

When to Use Numbered Lines

Code review comments reference specific lines — pasting numbered code into a chat thread is faster than sharing a screenshot. Legal documents and academic papers cite text by line for precise quotation. Translators use line-numbered source files to keep parallel translations aligned. Educators distribute numbered handouts so the whole class can find the same passage instantly. QA testers attach numbered logs to bug reports so engineers can pinpoint the failing line.

Why Format Matters

The default 1. text format reads naturally in prose contexts. The [1] text bracket format is preferred in scientific writing because brackets visually separate the index from the content. The tab separator produces output that pastes cleanly into spreadsheets, where the number lands in column A and the text in column B.

Privacy

All numbering happens client-side in your browser. The text you paste is never transmitted, logged, or stored anywhere.

Count words and characters with the Word Counter. De-duplicate text with Remove Duplicate Lines. Sort lines alphabetically with Sort Lines.

Frequently asked questions

Can I start from a number other than 1?

Yes. Change the start number to any value.

What separators are available?

You can type any separator: period-space, colon, tab, dash, etc.

What does zero-padding do?

It adds leading zeros so all numbers have the same width (e.g., 01, 02... 99).

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