PHP fmod() Function: Usage and Examples

Use fmod() when you need to returns the floating-point remainder of a division in a PHP application. The examples below show the actual operation and its limitations.

What Is fmod() in PHP?

Returns the floating-point remainder of a division. The exact signature supported by your installation depends on its PHP version and enabled extensions.

Its syntax is:

fmod(float $num1, float $num2): float

Parameters and return value: The parameter types, optional arguments, references, and return type are shown in the signature above. Optional parameters are marked with an ellipsis in this reference signature.

Example 1: Basic Usage

<?php

echo fmod(7.5, 2.0);

Output:

1.5

Example 2: Different Input or Behavior

<?php

echo fmod(-7.5, 2.0);

Output:

-1.5

Practical Example: Applying the Function

<?php

$angles = [370.5, 725.25]; foreach ($angles as $angle) { echo fmod($angle, 360.0) . PHP_EOL; }

Output:

10.5
5.25

Important Behavior and Edge Cases

A zero divisor is invalid; floating-point representation may limit exactness.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• Returns the floating-point remainder of a division.
• A zero divisor is invalid; floating-point representation may limit exactness.
• % performs integer remainder; fmod() works with floating-point values.

Use fmod() for the specific operation demonstrated above. Check its prerequisites and handle failure conditions before using it with production data.