A very simple way to calculate the overall percentage is just to sum percentages of projects and divide the result by amount of projects. In your case it would be: (40% + 70% + 15% + 6%) / 4 = 32.75% That assumes that you consider each project to be equal in size or amount of required work. If that is not the case, you could add appropriate weights to project percentages before summing them up. I hope that helps.