PHP Variables – A Beginner-Friendly Guide

In PHP, variables are used to store data like text, numbers, or other values. Let’s walk through the basics step by step.

1. Declaring Variables in PHP

  • A variable always starts with a $ sign.
  • The name comes right after $ without spaces.

Examples:

$firstname = 'Fazli';
$secondname = 'Hassan';
$price = 15;

Here:

$firstname stores the string “Fazli”.

$price stores the number 15.

2. Variables are Case-Sensitive

In PHP, uppercase and lowercase letters matter!

$firstname = 'Fazli';
$FirstName = 'Jacob';

👉 These are treated as two different variables because of the capital F in $FirstName.

3. Rules for Variable Names

✅ Allowed:

  • Letters (a–z, A–Z)
  • Numbers (0–9) but not at the beginning
  • Underscore _

❌ Not Allowed:

  • Special symbols like -, @, !, etc.
  • Starting with a number

Examples:

$var_name = 'Valid – underscore is fine';
$var_name2 = 'Valid – number allowed after first letter';

$var-name = '❌ Invalid – hyphen not allowed';
$2var_name = '❌ Invalid – cannot start with number';

4. Displaying Variables (Output)

The two most common ways to display variables in PHP are echo and print.

Using echo:

echo $firstname;   // Outputs: Fazli
echo $price;       // Outputs: 15

Using print:

print $firstname;  // Outputs: Fazli
print $price;      // Outputs: 15

🔎 Difference:

The echo is slightly faster and can output multiple values at once.

The print returns a value (1), so it can be used in expressions—but usually, beginners just use echo.

5. Variable Naming Conventions

When working in a team or writing clean code, it’s best to follow consistent naming conventions.

Common conventions in PHP:

✅ camelCase

First word lowercase, following words capitalized.

Example:

$firstName = 'Fazli';
$totalPrice = 100;

✅ snake_case

Words are separated by underscores.

Example:

$first_name = 'Fazli';
$total_price = 100;

✅ PascalCase (less common for variables, more for Classes)

Every word starts with a capital letter.

Example:

$FirstName = 'Fazli';
$TotalPrice = 100;

Quick Summary

  • Variables start with $
  • Case-sensitive ($name ≠ $Name)
  • Valid names can contain letters, numbers (not at start), and underscores
  • Use echo or print to display values

✨ With these basics, you’re ready to start working with variables in PHP!