PHP If Else Statements: Conditions Explained

if runs code when a condition is true. Add else to run something different when it is false.

index.php

PHP

<?php
$age = 15;

if ($age >= 18) {
    echo "Adult";
} else {
    echo "Minor";
}

Output

OUTPUT

Minor

Exactly one of the two blocks runs, never both and never neither.

index.php

PHP

<?php
$isLoggedIn = false;

if ($isLoggedIn) {
    echo "<a href='/logout'>Log out</a>";
} else {
    echo "<a href='/login'>Log in</a>";
}

Output

OUTPUT

<a href='/login'>Log in</a>

A discount rule

index.php

PHP

<?php
$cartTotal = 450;

if ($cartTotal >= 500) {
    $shipping = 0;
} else {
    $shipping = 49;
}

echo "Shipping: $shipping";

Output

OUTPUT

Shipping: 49

The early return pattern

Inside a function, you can often skip else by returning early. The code becomes flatter and easier to read.

index.php

PHP

<?php
function describeAge(int $age): string
{
    if ($age < 0) {
        return "Invalid age";
    }

    if ($age >= 18) {
        return "Adult";
    }

    return "Minor";
}

echo describeAge(20) . "\n";
echo describeAge(-5);

Output

OUTPUT

1
2

Adult
Invalid age

Compare that with one deep if ... else if ... else chain. The early return version has no extra nesting.

else needs an if

else cannot stand alone. It always belongs to the if directly above it.

lightbulb

Handle the unusual case first

When a function has a special case (invalid input, empty list), deal with it at the top with return. The main logic then runs without extra nesting.

A real example: login state

A discount rule

The early return pattern

else needs an if

Handle the unusual case first