PHP bindec() Function

The bindec() function in PHP converts a binary string (base-2) into a decimal number (base-10).
It accepts a string of 0s and 1s and returns the equivalent integer or float.
This is useful for working with binary data, flags, permissions, or bitwise operations.
It’s the opposite of decbin(), which converts decimal to binary.
Example: bindec("1101") returns 13.

Syntax


bindec(string $binary_string): int|float

  • $binary_string: A string containing a valid binary number (only 0s and 1s)
  • Returns: The decimal (base-10) value as an int or float

File Name: bindec-example.php


<?php
echo bindec("1101");     // ➤ 13
echo "\n";
echo bindec("101010");   // ➤ 42
echo "\n";
echo bindec("11111111"); // ➤ 255
?>

Use Cases

Use Case Description
Binary to decimal For decoding binary input or file headers
Low-level bit operations Handling flags, bitmasks, permissions
Networking IP subnet masks, binary headers

Summary

Function Description
bindec() Converts binary to decimal
Input Binary string (e.g. "1010")
Output Decimal integer or float