[anifow]

Yes, the author is pretty off-the-mark and I would say misleading. Here are some scenarios worked out with www.numbercanvas.com

Early Retirement, Average Lifespan: $1 million

Early Retirement, Long Lifespan: $1.5 million

Average Retirement, Long Lifespan: $1.25 million

Average Retirement, Average Lifespan: $650,000

Early Retirement, Short Lifespan: $480,000

http://pastebin.com/QU5dnCe8

[Ntrails]

Expected joint life at early retirement (which is what the article prices) in the US is ~35 years assuming spouse of similar age to the retiree (looking at http://www.irs.gov/pub/irs-pdf/p590.pdf from a quick google).

The 4% was not defined as real return, maybe it was supposed to be - but otherwise you need to account for the inflation linkage of the annuity.

With that basis you get $1.4m with no inflation and almost exactly $2m with an inflation assumption of 2%.