Definition
Available to promise (ATP) is the quantity of an item you can still commit to new customer orders: stock on hand minus what is already reserved for other orders.
What is available to promise used for?
Salespeople who quote from on-hand stock alone end up promising goods that already belong to another customer. ATP fixes that. Fuller definitions also add stock arriving on open purchase orders by the date it’s due.
Available to promise for one item
Example- On hand
- 500
- Reserved for confirmed orders
- −320
- Arriving next week on a PO
- +200
Available today
180
ATP is per warehouse; stock held in another branch may need a stock transfer first. Reservations come from confirmed orders, see stock reservation.