Merrill Lynch has this retirement calculator online, which is one of a number available. It has an annoying talking voice, but you can mute it. It is an interesting calculator, in that it may assure you that you are well on-track to a comfortable life, or it may panic you by illustrating how underfunded your retirement plan really is.
For me, it was reassuring.
Note: I am not endorsing or recommending Merrill Lynch or Merrill Edge. I do not use their investment services, personally.