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How long $1 million actually lasts, the full math. The setup: $1 million invested, growing at a steady 7% average return, while you pull out the same amount every month. The whole table comes down to one number. $1 million at 7% produces about $70,000 a year, which is $5,833 a month. Spend less than that and the portfolio grows faster than you drain it. That's what makes the Forever rows possible: at $4,000 a month you'd have $1.32 million after 10 years, $1.96 million after 20, and $3.24 million after 30. Spend more than $5,833 and the clock starts. $6,000 barely crosses the line, which is why it still stretches 51 years. At $15,000 a month you're draining it faster than it can recover, and it's gone in about 7. The catch: real markets don't return a steady 7%. A crash in your first years of retirement can sink a portfolio the averages said would survive, which is exactly why the 4% rule exists as the cautious version of this math. Treat Forever as the average case, not a promise. Follow for more investing math like this.