I am looking for either a website or software that will allow me to test different portfolios over time. Essentially i want it to tell me annual income based on holdings and show me the performance of the portfolio over a ten year period. I would also like it to be able to compare three different portfolios so I can see which one performed better. I don't know if there is a free one online or if it is something I may have to pay for and download which is fine as long as it accomplishes these tasks. Any suggestions would be appreciated.