This paper presents a simple graphical method for determining the minimum hydrogen demand. In the pure hydrogen load versus flow rate diagram, the sink and source composite curves are constructed, and they can shift freely in every direction. Through moving the hydrogen source composite curve to the position at which the two composite curves intersect at only two points, the hydrogen pinch point of the system is identified. Furthermore, the minimum utility consumption can be determined from the diagram. This method is simple, efficient, and easy to understand. It can be used in hydrogen systems with any utility concentration.