Sorry glass I've only just seen this. Most unhelpfully, it rather depends on the type of rice.
White basmati: allow 11/2 cups water to 1 cup rice and cook for only 10 minutes in a covered pan (absorption method), providing you have rinsed it well before cooking and, preferably, then left to soak for 10 minutes in cold water. Brown basmati should be prepared in the same way, but cooked for 25 minutes.
Other white long-grain rices are best cooked in an open pan. In other words, bring a large pan of salted water to the boil, add the rice, bring back to the boil and cook for 12–15 minutes (white) or 30–40 minutes (brown/wholegrain). Drain well and rinse with boiling water.
Thai fragrant rice: Allow 11/4 cups water to 1 cup rice and cook by the covered absorption method. Do not add salt. Thai rice takes a little less time than basmati.