Six Best Calculators for Figuring Out Your Retirement Strategy

Part of planning for retirement is a math exercise -- figuring out how much money you have, how much you need and how to best save enough to build a big enough nest egg before you hang up your work boots.

It's not calculus, but figuring this out without help isn't easy either. Fortunately, there are dozens of free online calculators that will help you. Here are six of the best.