What if?

  1. The question

    What if I invested $1,000/month?

    $1,000 monthly into the S&P 500 since 2015. USD, not EUR — we do not convert euros. Historical monthly DCA versus weekly-equivalent sizing.

    Quick answer

    If you invested $500/month into S&P 500 from 2020-01-03 through 2026-10-16, total contributions would have been about $40,960 and a blind DCA portfolio would be worth about $72,893 (+78%) on this historical path — before fees and taxes.

  2. Assumptions

    What this page actually assumes

    • $1,000 per month in US dollars. There is no EUR series yet, so this is the honest stand-in for “€1,000/month.”
    • Buys land on the monthly cadence used in our backtest (not 12 identical weeks).
    • Held to the last date. No withdrawals.
    • SteadyGrow still thinks in weekly signals; the comparison on this page is that monthly cash habit versus adaptive weekly sizing of the same long-run budget.

  3. Historical data

    2020-01-03 → 2026-10-16

    S&P 500 from 2015. Monthly contributions are the calendar most payroll savers actually use. Switch years to shorten the window; we will not extend it into the 1990s.

    Series: S&P 500. Same contribution calendar. No data before 2015.

  4. Interactive simulation

    Change the habit, stay on the real curve

    Amount
    Start year

    $500/month · S&P 500

    2020-01-03 → 2026-10-16 · $500/month · S&P 500

    Contributed$40,960
    Held to the last date$72,893
    Return+78%
    S&P 5002020-01-03 → 2026-10-16 · $500/month
     +$31,933 vs cash inEnded $72,893 on $40,960 contributed
    Portfolio (DCA)Cash contributed
    $0$19k$37.9k$56.9k$75.8k2020-012021-052022-092024-012025-062026-10

  5. Results

    What the numbers say

    Contributions ≈ months × $1,000. Ending value is that cash in the index. If you think in weekly pay, try the $500/week story — it is a close cousin, not the same schedule.

    The chart marks portfolio value over time for fixed-amount DCA and (when shown) a same-capital lump sum. Contributed cash rises in steps; ending value is mark-to-market on the last date (2026-10-16).

  6. What changes if…

    How did we calculate this?

    • Window: real market history from our published backtest bundle, typically from 2015 through the latest Friday in the series — we do not invent older decades.
    • Contribution calendar: the engine runs on a weekly Friday grid. A “monthly” habit is converted to an equivalent weekly cash rate ((amount × 12) / 52) so the same engine can compare habits.
    • Purchase timing: each period’s contribution is applied on that week’s bar in the series (close-based weekly path), not an intraday open fill.
    • Assets: S&P 500, Bitcoin, and other series we publish — USD only. No FX conversion.
    • Shares: fractional units are assumed. No brokerage commissions, bid–ask, or slippage are modeled.
    • Dividends / income: returns follow the wealth path in the backtest bundle for that asset (not a fixed 7–10% toy rate).
    • Lump sum (when shown): the same total cash as the DCA habit, invested on day one of the window, then marked to the same path.

    Frequently asked questions

    What if I invested $1,000/month?
    From 2020-01-03 to 2026-10-16, $500/month into S&P 500 contributed about $40,960 and a blind DCA habit ended near $72,893 (+78%).
    Are these numbers a forecast?
    No. They replay published market history from 2015 onward. Future returns can look nothing like this window.
    What assumptions matter most?
    Start date, contribution size, weekly vs monthly cadence, and whether you held through drawdowns. Fees and taxes are not modeled.
    Can I change the amount or start year?
    Yes — use the chips on this page when available, or open a related what-if / calculator with a different habit.
    How is this different from a 7% compound calculator?
    Fixed-rate toys assume a smooth return. We mark contributions to a real index/crypto path, including crashes in the window.
    What if I had traded instead?
    See The Boring Alternative for story-shaped counterfactuals (options losses, round-trips), then run the same dollars through an index DCA calculator.

    Run a related reality check

    Same contribution schedule, different assets — or a fixed-rate planning calculator when you want an illustration instead of history.

    S&P 500 vs BitcoinCompound interest →Boring Alternative →