Häufig gestellte Fragen
What does Available-to-Promise (ATP) mean?
Available-to-Promise (ATP), in German roughly "verfügbar zur Zusage", refers in the ERP context to the date-specific quantity of an item that can be firmly committed to new customer orders. Unlike pure stock on hand, ATP considers not only what is physically available but also deducts quantities already reserved and adds expected receipts from procurement and production. The ATP check thus gives sales a reliable real-time answer as to which quantity is actually still freely available at which date. ATP is therefore a cross-functional capability spanning sales, materials management, and production.
How is the ATP quantity calculated?
In simplified form, the basic formula is: ATP = physical stock + planned receipts − quantities already committed (reserved), with a defined safety stock often excluded on top of that. In time-phased systems, the calculation is not performed as a single value but period by period along a timeline, so that each future goods receipt is assigned to its expected date. Many ERP systems use a cumulative approach with look-ahead (cumulative ATP with look-ahead) that sums receipts and issues across several periods. The reliability depends directly on data quality, since incorrect replenishment lead times or outdated stock figures translate directly into faulty commitments.
What is the difference between ATP and CTP?
ATP checks exclusively against existing and planned quantities and assumes unlimited production capacity. Capable-to-Promise (CTP) goes one step further and additionally factors in free manufacturing and procurement capacity, meaning it also checks material, machine, and in some cases staff availability. This makes it possible to give a commitment even when the order still has to be produced and cannot be fulfilled from stock. CTP is often handled by an upstream Advanced Planning and Scheduling (APS) system, while the classic ATP check runs directly in the ERP.
Does ATP also take future goods receipts into account?
Yes, that is the key added value compared with a plain stock query. In addition to physical warehouse stock, ATP also factors in planned receipts, such as open purchase orders and production orders in progress, each with its expected receipt date. Quantities already committed are deducted from this total, producing a date-specific statement. Single-level ATP looks at one fixed point in time, while time-phased ATP shows period by period from when which quantity becomes available.
What is an ATP check used for in sales?
The ATP check ensures realistic and binding delivery dates right at order entry. Inside sales immediately sees whether and when a requested quantity can be delivered, avoiding both overambitious commitments followed by delivery delays and unnecessarily cautious dates that cost orders. Within process chains such as Order-to-Cash, the ATP check is an integral part of the order confirmation. It draws on the planned receipts and issues determined by MRP as its data basis.
Which ERP systems offer ATP, and how do they differ?
Practically all major ERP systems offer an ATP function, though with varying depth. SAP S/4HANA provides Advanced ATP (aATP), a rule-based variant that includes, among other things, backorder processing with confirmation strategies and product allocation (Product Allocation) for scarce items. Microsoft Dynamics 365 Supply Chain Management also offers ATP- and CTP-based delivery date determination, as do vendors such as Oracle and Infor. When comparing systems, it is worth checking whether the check is single-level or time-phased, whether multiple warehouses and sites are included, and whether safety stock can be excluded configurably.