Allow children to use time-out as a thinking experience. Tell them to think about what they did and what they can do different next time. Have them give you a report on what they thought about when the timer goes off. The length of time in time out varies from child to child. A rule of thumb is 5 minutes for children with Attention Deficit Hyperactive Disorder.
Normal children can go longer for major offenses.
Children new to time-out may want to leave the bathroom, walk around in the bathroom, argue, or be destructive. If this happens, just tell them that their time starts when they are doing what they are supposed to. Make sure the children understand that they are responsible if anything in the time-out area gets damaged or destroyed. Some children new to time-out will need to be carried to the place and the door may need to be held shut. If you are consistent with time-out, your child will eventually learn to go on their own and sit quietly for five minutes.