PHP bindec() Function

The bindec() function converts a binary number represented as a string into its decimal equivalent. The binary string is interpreted as an unsigned integer, and invalid characters (other than 0 and 1) are ignored.

Syntax

bindec(string $binary_string): int|float

Parameters

Return Value

Returns the decimal equivalent as an integer or float (for large numbers).

Examples

Basic Usage

Converting a simple binary string to decimal ?

<?php
    echo bindec('1111') . "<br>";        // Binary 1111 to decimal
    echo bindec('1010') . "<br>";        // Binary 1010 to decimal
    echo bindec('11111111') . "<br>";    // Binary 11111111 to decimal
?>

15
10
255

Handling Invalid Characters

The function ignores non-binary characters in the string ?

<?php
    echo bindec('1a1b0c1') . "<br>";     // Invalid chars ignored
    echo bindec('1111xyz') . "<br>";     // Invalid chars at end
    echo bindec('abc1010') . "<br>";     // Invalid chars at start
?>

101
15
10

Large Binary Numbers

For very large binary numbers, the function may return a float ?

<?php
    $largeBinary = str_repeat('1', 32);  // 32 ones
    echo "Binary: " . $largeBinary . "<br>";
    echo "Decimal: " . bindec($largeBinary) . "<br>";
    echo "Type: " . gettype(bindec($largeBinary));
?>

Binary: 11111111111111111111111111111111
Decimal: 4294967295
Type: integer

Conclusion

The bindec() function provides a simple way to convert binary strings to decimal numbers. It automatically handles invalid characters and can return either integer or float values depending on the size of the result.