Roughly 10cal/pound. The typical basal metobolic need is about 10 calories/pound/day. So, if you are just sitting in oneplace all day, the daily need for 150lbs person = 10x150=1500 calories. This 1500 cal is just keeping the 150lbs person even in 24 hours. If you are active, doing things etc...Then you will need more and this varies depending on level of activities you do. Good luck.