PHP hexdec() Function: Usage and Examples

Use hexdec() when you need to parses a hexadecimal number string into a PHP numeric value in a PHP application. The examples below show the actual operation and its limitations.

What Is hexdec() in PHP?

Parses a hexadecimal number string into a PHP numeric value. The exact signature supported by your installation depends on its PHP version and enabled extensions.

Its syntax is:

hexdec(string $hex_string): int|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 hexdec("FF");

Output:

255

Example 2: Different Input or Behavior

<?php

echo hexdec("10");

Output:

16

Practical Example: Applying the Function

<?php

$colors = ["0A","1F","7F"]; foreach ($colors as $hexValue) echo hexdec($hexValue) . PHP_EOL;

Output:

10
31
127

Important Behavior and Edge Cases

Large values may become floats, losing integer precision. Validate input before converting.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• Parses a hexadecimal number string into a PHP numeric value.
• Large values may become floats, losing integer precision. Validate input before converting.
• dechex() converts an integer into hexadecimal text.

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