mt_rand

Many random number generators of older libcs have dubious or unknown characteristics and are slow. By default, PHP uses the libc random number generator with the rand() function. The mt_rand() function is a drop-in replacement for this. It uses a random number generator with known characteristics using the « Mersenne Twister », which will produce random numbers four times faster than what the average libc rand() provides.

If called without the optional $min, $max arguments mt_rand() returns a pseudo-random value between 0 and mt_getrandmax(). If you want a random number between 10 and 100 (inclusive), for example, use mt_rand(10, 100).