The critical difference between a round bowl and an elongated bowl is,, the shape. The round bowl resembles a circle and tends to extend less into the bathroom, while the elongated model tends to protrude outward into the room from the front, because of its oval shape. The elongated bowl is approximately 18.5 inches long on average, while the round toilet is about 16.5 inches long on average. The round bowl is the conventional, traditional type, while the former has a more modern appeal.