What is ATP (Available-to-Promise)?
ATP is the quantity of a product that can be promised to customers based on current and planned inventory not yet committed to other orders.
Definition
Available-to-Promise (ATP) is a calculation that tells sales and order-management which uncommitted inventory is available to fulfill new customer orders by a given date. It nets on-hand stock and scheduled incoming supply against existing demand and reservations to produce a reliable promise. ATP enables accurate delivery commitments at the moment of order entry rather than optimistic guesses. It is a core capability for order promising in distribution and make-to-stock environments.
How ATP Works in ERP
When a sales order line is entered, the ERP runs an ATP check that compares requested quantity and date against projected available inventory, including open purchase and production orders. The system returns whether the order can be filled on time, the available quantity, or the earliest feasible date. Advanced configurations use rules for allocation, sourcing across locations, and substitutions to improve promise accuracy.
ERP Vendors with Strong ATP
Oracle NetSuite
The original cloud ERP — built for fast-growing companies
SAP S/4HANA Private Cloud
Fully customisable managed-cloud ERP for complex enterprises
Infor CloudSuite
Industry-specific cloud ERP suites on AWS
Microsoft Dynamics 365
Modular ERP + CRM tightly integrated with Microsoft 365
Frequently Asked Questions
What is the difference between ATP and CTP?
ATP promises based on existing and already-scheduled supply, so it answers what can be delivered from current plans. Capable-to-Promise (CTP) goes further by checking whether additional supply could be produced using available capacity and materials. ATP looks at what is planned; CTP evaluates what is achievable if you build more.
What does ATP take into account?
An ATP calculation nets current on-hand inventory plus scheduled receipts, such as open purchase orders and planned production, against committed demand and reservations. The result is the uncommitted quantity available to promise on specific dates. Multi-location and allocation rules can refine this further to reflect how a company prioritizes supply.