How the numbers are made.
MoneyTime Machine is an educational simulator. We're careful about what goes in so you can be confident about what comes out.
Data sources
Monthly closes are refreshed on the 2nd of every month:
- S&P 500, Nasdaq-100, International Stocks, US Bonds, Gold — Stooq monthly ETF closes (SPY, QQQ, EFA, AGG, GLD) as total-return proxies.
- Bitcoin — CoinGecko daily USD, collapsed to month-end closes.
- Cash — a synthetic 4% APY baseline compounded monthly.
How we simulate
Each scenario is a dollar-cost-averaging plan: you deposit the starting amount on month 0, then the monthly amounton the last day of every subsequent month. We convert deposits into units at that month's close and mark-to-market at every following month.
"Annualized" is the compound annual growth rate of the underlying asset over the window — not of your specific DCA plan. This is the honest number for comparing assets.
What we don't include
- Taxes, fees, or bid/ask slippage.
- Currency effects (all figures in USD).
- Dividend reinvestment for indices — the ETF proxies already embed distributions in their price series.
What this is not
This is not financial advice. Historical returns are a starting point for thinking, not a prediction. Bitcoin's history in particular is short and violent — don't extrapolate.