This is a big improvement to the original. Click or press Space after drawing your circle to get results, or turn on active calculations. The center is determined by the average of all the points on the circle, this way, you aren't struggling to make the circle around a predetermined point. Also the diameter doesn't matter. Red dot in the corner is to toggle active calculation of the percentage. This is because some people may not have the hardware required to do all the calculations every frame.
