A calculation based on the available-to-promise (ATP) figure in the master schedule. Two methods of computing the cumulative available-to-promise are used, with and without lookahead calculation. The cumulative with lookahead ATP equals the ATP from the previous period plus the MPS of the period minus the backlog of the period minus the sum of the differences between the backlogs and MPSs of all future periods until, but not to include, the period where point production exceeds the backlogs. The cumulative without lookahead procedure equals the ATP in the previous period plus the MPS, minus the backlog in the period being considered. Also see: Available-to-Promise.