ATP (Available To Promise) refers to the quantity of products that a company can commit to delivering to a customer on a given date, without jeopardising orders already accepted. It is the uncommitted portion of stock, as opposed to total stock, which includes quantities already reserved.
The calculation is simple in principle: ATP = available stock + planned receipts (purchase orders, expected production orders) − quantities already allocated to firm customer orders. By tracking this indicator, a salesperson or a planner can give a reliable delivery date, rather than promising stock that is in fact already committed — a classic source of delays and disputes.
ATP is distinct from CTP (Capable To Promise), which goes further by also checking the production capacity and the components needed to fulfil demand not covered by the planned stock. ATP reasons about what is available and planned; CTP simulates manufacturing feasibility.
This indicator is central to requirements planning (MRP) and order management. In eyeot, it is part of the Supply Chain module, which brings together stock, expected replenishments and customer commitments.