Kalender started his studies in physics and mathematics at the University of Bonn, Germany. He completed his master's and Ph.D. degree in medical physics at the University of Wisconsin in 1974 and 1979, respectively. In 1988 he completed all postdoctoral lecturing qualifications (Habilitation) at the University of Tübingen, Germany. In order to get a better grasp of the subject, he took and successfully completed all courses in the pre-clinical medicine curriculum.