Your personal retirement number depends on your lifestyle goals, investment risk and desired retirement age, among other key factors ...

One rule of thumb is that you'll spend 70%-80% of what you spent before retirement during retirement. Using the 4% rule, you can calculate how much you need to save in total.

Lucy Lazarony is an experienced personal finance journalist and writer who got her start in 1998 writing about financial topics. She writes accessible and easy-to-understand articles about credit, ...