mt_getrandmax

(PHP 4, PHP 5, PHP 7)

Show largest possible random value

int mt_getrandmax ( void )

Returns the maximum value that can be returned by a call to mt_rand().

Returns:

Returns the maximum random value returned by a call to mt_rand() without arguments, which is the maximum value that can be used for its max parameter without the result being scaled up (and therefore less random).

Examples:

Calculate a random floating-point number

<?php
function randomFloat($min = 0, $max = 1) {
    return $min + mt_rand() / mt_getrandmax() * ($max - $min);
}

var_dump(randomFloat());
var_dump(randomFloat(2, 20));
?>

The above example will output something similar to:

float(0.91601131712832)
float(16.511210331931)