Available-to-Promise
Definition
The uncommitted portion of current and planned inventory that can be promised to new customer orders. ATP tells sales what can be delivered, and when, without stealing from existing commitments.
In Practice
Available-to-promise nets supply against commitments over time: on-hand stock plus scheduled receipts, minus inventory already allocated to booked orders. The result is a time-phased picture, for example 300 units promisable now and another 500 promisable after next Thursday's inbound PO, which lets order entry quote realistic dates in real time.
ATP is where inventory data meets customer promises, so its integrity depends on everything upstream: accurate on-hand counts, honest PO due dates, and disciplined allocation. When any of those slip, ATP over-promises and customer service spends its days apologizing. More advanced variants, like capable-to-promise, extend the check to production capacity.
Example: a distributor's rep enters an order for 800 units against 500 on hand. ATP shows 400 unallocated today and a 1,000-unit receipt due Monday, so the system offers a split: 400 units shipping today, 400 shipping Tuesday, and the customer accepts on the call.
Related Calculators
Related Terms
The process of assigning available inventory to competing demands, such as customer orders, channels, or locations, especially when supply is insufficient to cover everything. It decides who gets stock when there is not enough for everyone.
On-Hand InventoryThe physical quantity of stock currently present in a location, regardless of whether it is committed to orders. It is what you would find if you walked out and counted the shelves.
On-Order InventoryStock that has been ordered from suppliers or other facilities but not yet received, represented by open purchase orders, transfer orders, or production orders. It is committed inbound supply.
Inventory AccuracyThe degree to which recorded inventory matches what is physically present, measured by comparing system records to physical counts. It is usually expressed as the percentage of records that match within tolerance.