How long is a human suppose to sleep?

This can vary however these are generally the standards New Born: 18 to 20 hours Growing children: 10 to 12 hours Adults: 6 to 9 hours Aged persons: 5 to 7 hours New borns need the most sleep as there cells are dividing exponentially and they are dividing the fastest. Growing children teens fall under this category this is when one usually hits one of their growth spurts and needs that sleep so their body can properly produced ATP (Adenosine Triphosphate) Adults bodies generally have stopped growing therefore they do not need as much sleep, and same thing with an aged person.
Depending on your age, anywhere from 7 - 10 hours.