I've tried lots of retirement income planners and one that I really like is the Fidelity Investments Retirement Income Planner. This is not a planner for someone who just wants a rough idea of how much money they need to save. This planner is for someone who is serious about figuring out what they'll need and where they stand (although you can bypass the detailed worksheets and get the rough estimate if you prefer).
I sat down with this planner and a printout from my financial program of my most recent annual expenses and filled it out in detail, trying to estimate what my expenses will look like post-retirement. The planner allows you to do things like plug in income from a retirement job, with starting and ending dates. You can also plug in lots of other very specific assumptions, like a future inheiritance or the sale of a house when you plan to downsize. If you take the time to fill these worksheets out it's a great exercise, not just to see if you have saved enough but also to start thinking about what expenses you need to plan for.
You have to be a Fidelity client to use the tool, but there is also a free trial available. Highly recommended!!