What if?

  1. The question

    What if I started in 2015?

    $500 a week into the S&P 500 from 2015 — the earliest window we can show honestly. Compare with starting in 2020 or 2022 using the chips below.

    Quick answer

    If you invested $500/week into S&P 500 from 2015-01-02 through 2026-10-16, total contributions would have been about $308,000 and a blind DCA portfolio would be worth about $593,507 (+92.7%) on this historical path — before fees and taxes.

  2. Assumptions

    What this page actually assumes

    • $500/week, S&P 500, no withdrawals.
    • “Started earlier” here means 2015, the first year on our weekly curves — not 10 years before that, and not a simulated childhood.
    • The comparison run starts in 2020 with the same weekly amount so you can see time-in-market on one page.
    • Year chips change the baseline start (and the comparison start if you pick a year). They never invent data before 2015.

  3. Historical data

    2015-01-02 → 2026-10-16

    2015–present includes a calm grind, a crash, a rebound, and a bear. A 2020 start skips the first five years of contributions and compounding. Both use the same Friday series.

    Series: S&P 500 and 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/week · S&P 500

    2015-01-02 → 2026-10-16 · $500/week · S&P 500

    Contributed$308,000
    Held to the last date$593,507
    Return+92.7%
    S&P 5002015-01-02 → 2026-10-16 · $500/week
     +$285,507 vs cash inEnded $593,507 on $308,000 contributed
    Portfolio (DCA)Cash contributed
    $0$154k$309k$463k$617k2015-012017-052019-102022-012024-052026-10

    $500/week · S&P 500

    Same $500/week, but starting in 2020

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

    Contributed$177,500
    Held to the last date$315,884
    Return+78%
    S&P 5002020-01-03 → 2026-10-16 · $500/week
     +$138,384 vs cash inEnded $315,884 on $177,500 contributed
    Portfolio (DCA)Cash contributed
    $0$82.1k$164k$246k$329k2020-012021-052022-092024-012025-062026-10

  5. Results

    What the numbers say

    The early start usually wins on total value because more cash went in for longer. That is the whole trick. It is not a personality difference; it is calendar math on a real index.

    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 started in 2015?
    From 2015-01-02 to 2026-10-16, $500/week into S&P 500 contributed about $308,000 and a blind DCA habit ended near $593,507 (+92.7%).
    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 →