The upper-bound of this value is platform-independent. PHP implements the 32-bit version of the Mersenne Twister ("mt"), so the maximum possible value is 2**31 - 1 (2147483647).
(PHP 4, PHP 5, PHP 7, PHP 8)
mt_getrandmax — Show largest possible random value
Returns the maximum value that can be returned by a call to mt_rand().
This function has no parameters.
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).
The upper-bound of this value is platform-independent. PHP implements the 32-bit version of the Mersenne Twister ("mt"), so the maximum possible value is 2**31 - 1 (2147483647).