Cooking rice in the microwave takes around 10 to 18 minutes.
Put the microwave in a microwave safe bowl and cover the rice with water and then place it in the microwave for 10 minutes and check the rice to see if it's done and if not add a bit more water if needed and then cook for another 8 minutes.
After 18 minutes the rice should be fully cooked but if it's not soft enough for you then you can cook it a few more minutes.
But usually 18 minutes is long enough for fully cooked rice in the microwave.