Available to Promise Calculation

Available to promise (ATP) is the uncommitted portion of a company's inventory or planned acquisitions. You use this amount to accurately promise customer orders. As long as manufacturing produces according to the MPS and sales makes commitments according to the ATP information, this method increases customer service and reduces inventory carrying cost.

ATP uses actual customer orders to identify inventory that can be promised to a customer. The time fence rule for planning has no effect on ATP. Forecast is never included in ATP calculations.

The system calculates the ATP quantity like this:

• First period ATP = on-hand balance − safety stock + work orders + purchase orders + planned orders − sales orders − work order parts list demand − interplant demand − unconsumed lot quantities that are expired.

• After the first period, ATP = work orders + purchase orders + planned orders − sales orders − work order parts list demand − interplant demand − unconsumed lot quantities that are expired.

  The system does not display negative ATP for the next periods. However, the system reduces the CATP by the negative amount.