Attack Calculator is for Dungeon Masters who lose their D20s or simply can\'t be bothered to roll all those attacks. Enter the required AC, Fortitude, Reflex or Will to hit in the Defense Score field, then enter any addition or subtraction to the roll in the \'Bonus\' field, and select the \"Attack!\" button.Attack Calculator will roll the attack for you, telling you the results (\"Hit\", \"Miss\", \"Critical Hit\").