dolly day dream

can anyone please tell me how wide my new build shower room door has to be i am reading contradictory info online 2 ft 6 inch standard and also 2ft 9 inches thanks in advance for any help

Hello everyone, i am doing a build in my garden and project managing it myself (wish i hadn't but hey ho). My next task is a studwall and i am thinking does this attach to the ceiling rafters. my instinct is yes it must. i just want confirmation so when a this is done i have some idea. Yes i am female never undertaken anything like this before but i am not as green as i am cabbage looking. And i have saved money.