text: You would have to add up all the prices of shares times the number of shares for the proper weighting they recive in the index or etf. Then add up all the earnings per share times the number of shares. Then divide those two numbers. \n\nThe forward P/E you would have to estimate NOT only what those companies will make next year, but what the companies  are added and what are dropped. This is not realy even possible assuming you had a good crystal ball to estimate what a company would make if you knew exactly which company to calculate it for.\n\nThat is a lot of work.