These are projections, not predictions. They assume a constant annual return compounded monthly. Real markets are uneven and include long losing stretches. Your actual result will not follow a smooth curve.

Where the rates come from. The index figure (~10%/yr) is the long-run historical nominal average of the US stock market including dividends. Gold (~7.7%/yr) is its average since 1971. Both are long-run historical averages, not guarantees. Gold went roughly 25 years (1980–2005) without gaining in real terms.

The market-cap approach. Rather than extrapolating past returns, this asks a cleaner question: if Bitcoin reached some share of gold’s roughly $30 trillion above-ground value, what annual return would that imply? Full parity within 20 years works out to about 15% a year — large, but not absurd, and grounded in a stated assumption you can argue with. It does hold gold’s value flat, which is unrealistic; if gold keeps appreciating, the target moves further away.

On the Bitcoin option. The rates offered are real historical CAGRs, but they are the most misleading numbers on this page. Bitcoin’s enormous early returns came from a starting price near zero; reproducing them from today’s market size is arithmetically impossible. It has also lost 70–80% of its value on several occasions and taken years to recover. A single smooth rate erases all of that. Treat the conservative setting as the only one worth planning around, and understand that even it may be far too optimistic.

How daily and weekly amounts are converted. A day is multiplied by 365/12, a weekday by 260/12, a week by 52/12. The familiar shortcuts — 30 days or 4 weeks to a month — undercount by roughly 1.5% and 8%. Choose weekday for anything you only buy on work days; treating a five-day coffee habit as seven overstates it by 40%.

Not included: taxes, fund fees, transaction costs, and the risk of needing the money early. Each reduces the outcome. It also assumes you never miss a transfer and never withdraw.

The catch nobody mentions: cutting an expense doesn’t create savings on its own. Most people absorb the freed-up money into other spending within a month or two. The transfer has to be automatic and out of reach, or none of these numbers happen.

Why it’s still worth seeing. The exact figure isn’t the point — the shape is. Small consistent amounts plus time do most of the work, and the growth eventually overtakes everything you put in.