I couldn't find the exact pixel dimensions for this calculator, so I just measured it myself.
1 Centimeter = 22 Pixels, exactly.
Edit: It might not appear in the photo to be an exact alignment with centimeters, but that's all because of the ruler sitting a little higher than the screen and the camera optical focus and crap.
Indeed, it's exactly 22px/cm
My demo is evolving, into split programs that are somewhat useful.