On Hand

This field maintains the total gross quantity on hand for this item (minus the non-nettable stock). That is, the total quantity of the item currently on hand displays, allowing you to compare this quantity to the requirements. The system calculates this amount automatically. The amount is updated whenever a receipt, adjustment or shipment is made, keeping the on hand amount current at all times.

The first record displayed on the Planning Detail form is balance on hand (as identified by the words "BALANCE ON HAND" in the Reference field). The balance on hand quantity accumulates the quantity on hand minus the quantity reserved for each item/warehouse record that exists for the item that is not set as a Dedicated Inventory warehouse.