Computer-implemented methods, and associated computer program products and systems, for checking availability of a ware in a time interval, a resource to produce the ware being associated with the ware. The computer-implemented method can include obtaining capacity supply information comprising a capacity supply for each date of the time interval and capacity demand information comprising a capacity demand for each date of the time interval. The first date of the time interval is set to a later date, there is determined for each date from the first date to the later date whether capacity supply is unused. If capacity supply is unused, the method includes eliminating the specific amount from the capacity supply information. In response to demand information representing a demand having a requested date, availability of the resource on the requested date is determined using the capacity supply information and the capacity demand information.