PHP Comments: Single-line, Multi-line, and DocBlock Explained with Examples

Introduction

When writing PHP code, adding comments is one of the most important best practices.
Comments help explain what your code does, making it easier to understand, maintain, and debug — both for you and others who read your code later.

In PHP, comments are non-executable lines that the interpreter completely ignores during program execution. They are meant for humans, not machines.

In this lesson, we’ll explore:

Types of PHP comments
How to use them effectively
Examples for each type
Why comments are crucial for good programming habits

What Are Comments in PHP?

A comment in PHP is a piece of text within your script that’s ignored by the PHP engine. It’s useful for:

Describing what a code block does
Temporarily disabling code during testing
Adding notes or documentation for future reference

Comments don’t affect the execution or output of a PHP program.

Types of Comments in PHP

PHP supports three types of comments:

Single-line comments
Multi-line comments
DocBlock (Documentation) comments

Let’s look at each type in detail.

Single-line Comments in PHP

Single-line comments are used to explain a specific line of code.
Everything after the comment symbol on that line is ignored by PHP.

You can create single-line comments using either:

Double slash (//)
Hash symbol (#)

Syntax:

Example:

<?php

// Define a variable


$name = "Jack";

# Display the name

echo "Hello, $name!";
?>

Add Your Heading Text Here

Explanation:
The comment lines are ignored by PHP — they only serve as notes for the developer.

Multi-line Comments in PHP

Multi-line comments are used when you need to write longer explanations that span multiple lines.

They begin with /* and end with */.

Syntax:

Example:

 
<?php

/*
The following code calculates
the
sum of two numbers and prints the result.
*/

$a = 10;

$b = 20;

$sum = $a + $b;

echo "The sum is: $sum";

?>

Explanation:
Multi-line comments are perfect for explaining logic, algorithms, or sections of complex code.

DocBlock (Documentation) Comments in PHP

DocBlock comments are special multi-line comments used for documentation purposes, especially when working with large projects or frameworks.

They begin with /** and end with */.
Inside, you can include annotations like @param, @return, and @author.

These are recognized by PHPDocumentor and other tools to generate automatic documentation.

Syntax:

Example:

<?php
/**

* Calculate the area of a rectangle

*

* This function takes length and width as parameters

* and returns the calculated area.

*

* @param float $length The length of the rectangle

* @param float $width The width of the rectangle

* @return float The area of the rectangle

*/

function calculateArea($length, $width) {
return $length * $width;

}

echo "Area: " . calculateArea(10, 5);

?>

Output:

Explanation:
DocBlock comments are essential for professional coding and help tools and IDEs (like VS Code, PhpStorm) show auto-completion and documentation.