Occupancy in a hotel is calculated by the number of engaged rooms divided by the number of vacant rooms that physically exist in a hotel. For example, if Occupancy is 65%, this means that 65 rooms are engaged if the hotel has a overall of 100 x rooms.
The occupancy prediction is a written/reported estimation of the number of rooms which will be sold/engaged on an recognized day and/or for a definite period of time. Examples would be a daily occupancy calculation, a scheduled occupancy estimate, quarterly, and even a full annual tenancy prediction. In other words, the occupancy percentage that the hotel predicts will eventually change.