How this is worked out
What will US$1 million be worth in 30 years?
A range from past periods, not a forecast.
Start year. 2026 looks ahead from today. An earlier year tests the method against what really happened.
Share invested in stocks. The rest is in 10-year Treasury bonds. Reset to this share every year.
What the money buys, as cash. The price rise is the consumer price index December to December from Damodaran’s table (from the Bureau of Labor Statistics). Past periods of 30 years that ended before 2026 overlap, so neighboring periods share most of their years and the range is narrower than it looks. Stocks are the S&P 500 with dividends and bonds the 10-year Treasury bond held one year and reinvested, before fees and tax. The United States had one of the strongest stock results of the 20th century; other countries had weaker ones. The future-dollar and start-year-dollar columns each come from their own percentile, so the low case in one is not the same period as the low case in the other.
Three cases, invested. A range from past periods of the same length, not a forecast and not a promise. Before fees and tax, United States only; other countries had weaker results.
The year you were born. Cash uses the consumer price index of the workbook files (1913 on, 2026 means January to August); the invested money uses Damodaran’s table (1928 on). The mix is the share in stocks you chose.
Your answer in words. In 30 years, prices have multiplied by 2.05 to 4.60 times in past periods (middle 2.81 times), so US$1,000,000 left as cash would buy what US$217,357 to US$487,470 buys in 2026 (middle US$355,982). Invested 60% in stocks and the rest in bonds, the middle case ends at US$13,051,924, which buys what US$4,869,792 buys in 2026 (low US$2,917,897, high US$7,384,211). This is a range from the 69 past 30-year periods that ended before 2026, not a forecast, before fees and tax. The period ends in 2055, after 2025, the last year of history, so there is no real result to compare yet.
Some choices came from your profile.
US inflation 3.4% (August 2026, US Bureau of Labor Statistics)
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