If you have researched retirement at all (early or otherwise), you’ve probably ran across various retirement calculators online. You input how much money you have (or plan to have), your asset allocation, and it spits out some numbers. This Vanguard Retirement Nest Egg Calculator is a good example of a simple version.
Let’s try an example. If I am 40 years old and thus assume I have up to 50 years left in retirement, and I want to maintain a 4% withdrawal rate ($40,000 a year from a $1,000,000 portfolio that is 65% stocks/30% bonds/5% cash), the tool uses Monte Carlo simulations to calculate that I have an 80% chance of lasting 50 years.

There is effectively one output: the odds of not running out of money. Either you still have at least a dollar, or you don’t. In my example, I have an 80% chance of having $1 or more at age 90.
But what if you also considered the odds of running out of time? Yes, that’s a euphemism for dying. (Ever notice how many of those we have?) In another neat tool from Engaging-Data.com, Will Your Money Last If You Retire Early? adds some helpful nuance to this analysis. You input the same types of information, but now in any given year you are provided the overall odds of each of these things happening:
- Red – You are alive, but ran out of money.
- Light green – You are alive, with less money than you started with. (Kinda nervous?)
- Green – You are alive, with between 100% and 200% of what you started with. (Nice and comfy.)
- Dark green – You are alive, with over 200% of what you started with. (In hindsight, I didn’t need to save so much…)
- Grey – You are pushing up daisies. (In hindsight, maybe should’ve retired earlier…)
Here are sample results for the early retirement scenario above at 4% withdrawal rate (age 40, retirement horizon 50 years, $40k from a $1m 65/35/5 portfolio). I picked the female mortality table – if you have a male/female couple, it’s safer to pick the person likely to live longer.

There’s an angry streak of red where I’m broke. Of course, there’s a bigger streak of grey where I’m not breathing.
Here’s the same scenario, except with a lower 3% withdrawal rate ($30,000 a year from a $1,000,000 initial portfolio):

That change got rid of the red, but there is a lot of dark green. (1% makes a big difference.)
Here are sample results for a more traditional retirement scenario: (age 65, retirement horizon 25 years, $40k from a $1m 65/35/5 portfolio)

As a financially conservative person, these charts help illustrate why I prefer working with a 3% safe withdrawal rate for early retirement (50 and under) and 4% safe withdrawal rate for traditional retirement (closer to 65).
My favorite part of this tool is that it makes you take into account your mortality. It’s not all about staying above $1 in the bank, but also about maximizing your years of freedom. If you’re 40, you have a 10% chance of dying before even reaching 65. (This is why most people know someone who died shortly after retirement.) Is it better to have zero chance of broke and be 70, or 5% chance of broke and 60 with 10 more years of retirement (and 10 fewer years of work)? It is better to live a little more luxuriously for shorter time, or a little more frugally for a longer time? Playing around with all the different input variables might help you weigh the options.
Should a person who retires at age 70 withdraw the same amount of money from their portfolio as someone who is age 40? You’re talking about a retirement period that is likely twice as long as the other. In an article titled
When it comes to making your portfolio last a lifetime, you may be surprised at how long that might be. According to this Vanguard longevity tool, for a couple both age 40 today, there is a 50% chance that one will live to 88. That’s 48 years.
Here’s an interactive “game” at 






The 

Barron’s has released their 
Updated April 2018 with custom ETF allocations. Betterment is an independent hybrid digital/human advisor that will manage a diversified mix of low-cost index funds and help you decide how much you’ll need to save for retirement. (By independent, I mean that they are not tied to a specific brand of funds like Vanguard or Schwab). Betterment is also an RIA, which means they have a legal fiduciary duty to keep client interests first. They frequently announce new features and improvements, so I will work to keep this feature list updated.

Here’s a reader question regarding my most recent 



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