How to Declare Variables in PHP: Simple Syntax and Examples

In PHP, you declare a variable by starting with the $ symbol followed by the variable name, like $variableName. You assign a value using the = operator, for example, $age = 25;.

Syntax

To declare a variable in PHP, use the $ sign followed by the variable name. Then use the = sign to assign a value. End the statement with a semicolon ;.

• $: Indicates a variable.
• variableName: The name you choose for your variable.
• =: Assignment operator.
• value: The data you want to store (number, text, etc.).
• ;: Ends the statement.

php

<?php
$variableName = value;
?>

Example

This example shows how to declare variables with different types of values and then print them.

php

<?php
$name = "Alice";
$age = 30;
$height = 1.65;
echo "Name: $name\n";
echo "Age: $age\n";
echo "Height: $height meters\n";
?>

Output

Name: Alice
Age: 30
Height: 1.65 meters

Common Pitfalls

Common mistakes when declaring variables in PHP include:

• Forgetting the $ sign before the variable name.
• Using invalid characters in variable names (only letters, numbers, and underscores allowed, and cannot start with a number).
• Missing the semicolon ; at the end of the statement.
• Trying to use variables before declaring or assigning them.

php

<?php
// Wrong: missing $ sign
name = "Bob"; // This causes an error

// Correct:
$name = "Bob";
?>

Quick Reference

Concept	Description	Example
Variable sign	Always start with $	$age = 25;
Variable name	Letters, numbers, underscore; no starting number	$user_name = "John";
Assignment	Use = to assign value	$score = 100;
End statement	Use semicolon ;	$height = 1.75;
Valid values	Strings, numbers, floats, booleans	$isActive = true;

Key Takeaways

Always start PHP variable names with the $ sign.

Use only letters, numbers, and underscores in variable names; do not start with a number.

End each variable declaration with a semicolon ;.

Assign values using the = operator right after the variable name.

Avoid using variables before declaring or assigning them.