A casting tolerance proofing tool adapted to be implemented with a computer system. The computer system has a processor and a memory storing a CAD object of an apparatus to be manufactured with a casting process. The proofing tool includes a criteria selector operable to prompt for and receive a type of casting process for the apparatus to be manufactured with, and an extractor operable to determine a nominal dimension and a related tolerance from the CAD object. The proofing tool further includes a comparator operable to compare the tolerance with a first threshold and a second threshold.