That's a good point about tax advantaged accounts, since you get to save that money from your gross income. Ultimately, while the math roughly works, things are a bit more nuaunced than implied in the (otherwise very excellent) post I linked. I always like plugging my retirement savings goal into various savings calculators and playing around with how long it will take to reach that amount at various savings rates. Thus, for example, if I want to accumulate $500,000 (of today's money) in 10 years, and I anticipate 5% real returns after inflation, I need to save approximately $3350/month.