Available-to-Promise (ATP)
Available-to-Promise (ATP) is the availability check in the ERP that answers in real time which quantity of an item can be firmly promised for which date. ATP considers not only current stock but also planned receipts and already reserved quantities — the basis for realistic delivery dates.
What ATP actually calculates
ATP calculates the freely promisable quantity from several figures:
- Plus: physical stock and planned receipts (open purchase orders, production orders)
- Minus: quantities already promised/reserved for other orders
The result is the quantity that can be promised to a new order without conflict — including the earliest possible date.
ATP vs. CTP — available vs. feasible
- ATP (Available-to-Promise): checks against existing and planned stock — "is it there or arriving as planned?"
- CTP (Capable-to-Promise): goes a step further and checks whether additional production with free capacity and material can still deliver — "can we still make it?"
CTP is more computation-intensive and usually part of APS systems (Advanced Planning and Scheduling).
ATP in ERP and sales
In the order-to-cash process, the ATP check runs right at order entry: sales sees immediately whether and when delivery is possible. This avoids over-promising and scheduling conflicts. Modern ERP systems (SAP S/4HANA with advanced ATP, Microsoft Dynamics 365, Oracle) offer rule-based ATP with backorder processing.
Related topics
- MRP — Material Requirements Planning
- APS — Advanced Planning and Scheduling
- Order-to-Cash
- Material Planning
Frequently Asked Questions
What does Available-to-Promise mean?
Available-to-Promise (ATP) is the ERP availability check that shows in real time which quantity of an item can be firmly promised for which date — based on stock, planned receipts and already reserved quantities.
What is the difference between ATP and CTP?
ATP checks against existing and planned stock. CTP (Capable-to-Promise) goes further and checks whether additional production with free capacity and material can still deliver.
What is an ATP check for?
It ensures realistic delivery dates. At order entry, sales sees immediately whether and when delivery is possible, avoiding over-promising and scheduling conflicts.
Does ATP consider future goods receipts?
Yes. ATP counts not only physical stock but also planned receipts such as open purchase and production orders — minus quantities already promised.
Which ERP systems have ATP?
Virtually all larger ERP systems offer ATP. SAP S/4HANA has advanced ATP (aATP); Microsoft Dynamics 365 and Oracle also offer ATP functions with backorder processing.