An "interest-only" retirement plan can fund your retirement without draining your savings, but you will need to save a lot of money to make it possible. NerdWallet crunched the numbers, and we can tell you how much you need to save every month, broken down by age, to get $65,000 every year in an "interest-only" retirement. Check out this video to learn how much you will need in order to make it a reality.