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Investment Time Machine

What if you had invested years ago? Search any listed symbol, pick your start month, and model lump-sum or DCA with optional compare & S&P 500 — powered by live monthly prices when available.

Popular scenarios

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AAPL logo

Apple Inc.

$

Search any ticker — or jump in with one of these one-tap scenarios. We pull monthly adjusted closes and chart your hypothetical portfolio against SPY in seconds.

How it works

  1. Search any Yahoo-listed symbol — US equities, many ADRs, ETFs like SPY, and crypto pairs such as BTC-USD.
  2. Lump sum invests once at the first monthly close on or after your start date. DCA invests the same dollar amount every month through today.
  3. Advanced adds a second symbol and optional SPY line for context. Use Copy results, Download PNG, or your browser share sheet to pass scenarios around.

Understanding your results

  • Dividends are not modeled in price-only series — total return for dividend stocks and SPY would be higher.
  • Taxes, fees, and slippage are excluded.
  • Yahoo Finance is an unofficial data source and may be rate-limited. Use Use offline demo if live data fails.

Frequently asked questions

How does the Investment Time Machine calculator work?
Pick a ticker, a start month, and a dollar amount. We pull monthly adjusted closes from Yahoo Finance and simulate either a lump-sum (one-time) or dollar-cost-averaging (monthly) investment from that month through today, then chart the resulting portfolio value alongside the S&P 500 benchmark.
What returns are realistic for $1,000 in Bitcoin in 2015?
In January 2015 BTC traded near $300. A $1,000 lump-sum entry from that date has historically grown well over 100x at peak — see the live calculation for the current figure. Past performance does not guarantee future returns.
Does this calculator include dividends and stock splits?
It uses Yahoo Finance’s adjusted close series, which incorporates stock splits and special distributions automatically. Regular cash dividends are reflected in the adjusted price for total-return calculations on dividend-paying stocks, ETFs, and indices.
What is the difference between lump sum and DCA in this tool?
Lump sum invests your full amount once at the first monthly close on or after your start date. Dollar-cost averaging (DCA) invests the same amount every month from the start date through today — useful for modeling a recurring contribution like a 401(k) or systematic plan.
Can I compare two stocks against each other?
Yes. Switch the calculator into Advanced mode and add a second ticker in the “Compare” field. Both run on the same start date, dollar amount, and contribution mode, with the SPY benchmark line on the chart for context.
Which symbols are supported?
Anything Yahoo Finance lists — US equities (AAPL, MSFT, NVDA, TSLA), ADRs (TSM, ASML), ETFs (SPY, QQQ, VOO), indices (^GSPC, ^IXIC), and crypto (BTC-USD, ETH-USD, SOL-USD). Type a name or ticker to search.
Is the data live or delayed?
Monthly closes are end-of-month figures, sourced from Yahoo Finance and refreshed daily. This calculator is designed for historical scenarios, not intra-day quotes.
Are taxes, fees, or slippage included?
No. The simulation is a clean “what-if” on price — taxes, brokerage fees, bid-ask spread, and currency conversion are excluded. Treat the result as an upper-bound illustration.
Does TECHi save my searches?
Recent searches are stored only in your browser via localStorage so you can quickly revisit your last few scenarios. Nothing is sent to a server. Click “Clear” in the recents panel to wipe them.

Disclaimer

For education and illustration only. Not investment advice. Past performance does not guarantee future results.

Assumptions and disclaimer

Calculator outputs are educational estimates, not financial, investment, tax, or legal advice. Results depend on the inputs and assumptions shown on the page and may exclude fees, state rules, market volatility, liquidity, or timing effects. Verify figures with current sources and consult a qualified professional before making decisions.

The Power of Hindsight in AI & Tech Stocks

Why This Tool Is So Valuable

This simulator uses real historical price data to show what your investment would be worth today if you had bought at different times. It is incredibly eye-opening for volatile names like NVDA, TSLA, or the broader tech sector during the AI buildout.

Key Lesson

The biggest gains in major technology cycles often come after long periods of doubt and drawdowns. This tool helps build the discipline needed to hold through volatility in the AI economy.

How to Use This Tool Well

  • Try "buying" during previous tech bubbles and crashes — it builds real perspective.
  • Compare lump sum vs dollar-cost averaging entries on the same stock.
  • Use it to stress-test your own behavioral biases before making concentrated bets in AI names.