How much taller is a 215 tire vs a 205?

Depends on the aspect ratio of the tire. For instance a 215/70-16 and a 205/75-16 are almost the exact same diameter with the 205 tire being 1/4" larger in diameter because it has a larger aspect ratio. For all practical purposes they are the same height. I would have to know the aspect ratio of both tires to answer the question.