WIP — work in progress — is the value of materials that have left the shelf but have not yet come back as finished goods: money standing on the factory floor in the shape of half-made things. Per work order it is one subtraction:
materials issued (at their real cost) − output received (at standard cost)
While an order is open, a WIP balance is normal and healthy — it is the production under way. The balance is held in the chart's work-in-progress account, added to by every issue and relieved by every receipt, each entry narrated with its work order's code.
Closing the order empties its slice: the remainder — positive when the make consumed more than the standard says the output is worth, negative when it consumed less — is posted to the manufacturing variance account, and that remainder is the order's variance (§10.9). Two habits follow. An order left released forever keeps its WIP hostage, which is what the cockpit's WIP tile is quietly pointing at; and the factory's true efficiency story is read across closed orders, never from one order mid-flight.