I was psyched when I saw they developed a retirement calculator, but I tried it out just now and find it generally worthless.
As previously mentioned, retirement only goes as early as 40 years old.
It projects your stash forward from this point, and pulls the trigger on retirement regardless of whether your stash is "big enough." Would like to see a dollar amount (or rather, withdrawal rate) trigger instead.
And yet, even if you push the retirement age forward far enough that all cases result in >4% WR, the success rate is still <90%. Probably because...
Tax rate on $30,000 is mind-blowingly high. It assumes $37,500 withdrawal to result in $30,000 net. That's effective tax rate of $20% (!!!) And yet...
It uses >9% average returns but doesn't include inflation?
It only shows the "median" and "worst case" cases, not the "best case". I guess trying not to get people's hopes up.
I do like that they included Social Security in the simulation.
I hope they work on it some more, it could end up being really cool.