Calculators for retirement scenarios?

[dividend]

Is there a good online calculator for non-traditional retirement, that will let me run scenarios?

For example, I'm 30. Let's say I wanted to retire at 40. I'd be able to start drawing off my retirement accounts at 59 1/2, so I'd need to be able to get by for 19 1/2 years on taxable investment income, but I wouldn't necessarily be worried about not drawing it down since I'd only need that to bridge me to actual retirement age.

I'm not saying this is my plan, but I'm having trouble figure out what numbers are necessary to see if it's even possible. I'd like a calculator that would work backwards, i.e. I tell it how much I need to have, and it outputs a required monthly contribution. Do these types of calculators exist? Or should I just crunch the math by hand?

[DVM gone riding]

I liked this one bec it adjusted for inflation and asked more questions.
cgi.money.cnn.com/tools/retirementplanner/retirementplanner_101.jsp

[ziyia]

Here's my favorite one: www.flexibleretirementplanner.com/.
It lets you play around with various inflation rates, variations on rates of return, etc. It will let you separate taxable, tax free, and tax deferred investments, and tell it which order you want to draw them down in (and when). It also lets you play with things like one time cash inflow events or expenses, going back to work, etc etc.
I'm not sure it will work backwards, but you can certainly play around with inputs to see what would get you where you need to go.

[Gardening Grandma]

That last one is pretty interesting. The one thing I can't figure out, though is that it shows our IRA accounts as being depleted and the taxable account growing enormously. And our taxable account is a fraction of the IRA accounts....

[strider]

Apr 1, 2011 14:57:42 GMT -5 @ziyia said:

Here's my favorite one: www.flexibleretirementplanner.com/.
It lets you play around with various inflation rates, variations on rates of return, etc. It will let you separate taxable, tax free, and tax deferred investments, and tell it which order you want to draw them down in (and when). It also lets you play with things like one time cash inflow events or expenses, going back to work, etc etc.
I'm not sure it will work backwards, but you can certainly play around with inputs to see what would get you where you need to go.

Awesome site.