It depends on the brand of tire but here is how you calculate it.
225/75R16 => 225 is tire width in mm, 75 is ratio of tire width/tire height (of 1 side), 16 is rim diameter in inches.
tire diameter/height = 225 x 0.75 x 2 / 10 / 2.54 + 16 = 29.3 in
230/70R16 => 230 is tire width in mm, 70 is...