About the Add Line Numbers
The Add Line Numbers tool is a free, browser-based utility that instantly prepends sequential numbers to each line of your text without requiring login or uploading to servers. It processes entirely in your browser for complete privacy and works with any text content—from code snippets and logs to poetry and lyrics. The tool offers customizable formatting options, allowing you to choose numbering styles, skip empty lines, or add custom prefixes and suffixes to suit your exact needs.
How Add Line Numbers works
The Add Line Numbers tool works by splitting your input text into individual lines and automatically assigning an incremental number to each one. The entire process happens instantly in your browser with no data leaving your device.
How to use it:
- Paste or type your text into the input box
- Select your numbering format (standard numbers, dot notation, brackets, or custom pattern using %n as placeholder)
- Choose whether to number all lines or skip empty lines
- Click the button to generate your numbered text
- Copy the result instantly
Worked example:
Input text:
function hello() {
console.log("Hi");
}
Output (standard format):
1. function hello() {
2. console.log("Hi");
3. }Output (custom format with brackets - "[%n] "):
[1] function hello() {
[2] console.log("Hi");
[3] }How to use
- Type or paste your text into the input box.
- The result updates instantly as you type.
- Click Copy to use the output.
Common uses
- Debugging code by referencing specific line numbers in error reports or test failures
- Numbering documentation, instructions, or procedures for clear step-by-step referencing
- Adding numbers to song lyrics, poetry, or scripts for easier discussion and annotation
- Preparing text logs or data files for analysis where line position matters
- Creating numbered lists with consistent formatting for legal documents, contracts, or formal requirements
- Testing applications that validate user input on a line-by-line basis