This page aims to help you estimate the amount of money you will have after a long time if your yealy save a certain amount. You may specify the duration of savings, the amount saved in the first year, the estimated annual benefits (eg interest paid by banks, performance of bonds, etc.) and the increase of the amount you are able to save in each year.
The savings model is similar to the one used by insurance companies that offer packages that include a life insurance and a savings component. The page can be used to check if the yields offered are reasonable.