Quick-Start Guide

← Back to Chronoticker

A 1-minute walkthrough: what the inputs do, what the stats mean, and how to read the chart.

What this tool does

You pick a basket of stocks and weights — the tool simulates investing in that exact mix at a starting date and tracks what your money would be worth today, day by day. It compares your portfolio against the S&P 500 (via the SPY ETF) so you can see whether your picks beat or lagged a passive index.

How to run a backtest

1
Set your initial investment. The lump sum you'd invest at the start of the lookback window. Default $10,000.
2
Pick a lookback window. How far back to start. 1y is a quick sanity check; 5y or 10y shows how a strategy held up across multiple market regimes (e.g., COVID crash, 2022 bear market, 2023 AI rally).
3
Choose a rebalance cadence.
  • None (buy & hold) — buy once, never touch. Winners drift up, the portfolio gets concentrated.
  • Monthly / Quarterly / Annually — periodically sell winners and buy losers to return to your target weights. Reduces concentration risk and forces "buy low, sell high" mechanics.
4
(Optional) Add a monthly DCA contribution. Simulates dollar-cost averaging — adding the same dollar amount every 30 days, split across your weights. Useful for "what if I'd invested $500/month into the Mag 7?" questions.
5
Build your allocation. Pick stocks from the dropdown, set weights, and make sure they sum to 100%. The total turns green when you're balanced. Try the Mag 7 (equal weight) preset for a one-click starting point.
6
Click Run Backtest. The tool fetches historical adjusted-close prices from Yahoo Finance, aligns the trading days, simulates the strategy, and renders the chart + stats.

Reading the results

The chart

The orange line is your portfolio's value over time. The dashed navy line is what the same money would have done in the S&P 500 (SPY). Above SPY = you outperformed; below = you underperformed.

The stats

Final Value What your portfolio is worth on the last day of the window — including any DCA contributions you added along the way.
Total Return Profit divided by total dollars contributed. 50% means you made $0.50 for every $1 you put in.
CAGR Compound Annual Growth Rate — the steady annual return that would have produced the same end value. The fairest single number to compare strategies of different lengths.
Max Drawdown The worst peak-to-trough drop the portfolio ever experienced. This is the number that gets ignored and shouldn't be. A 30% CAGR with a 70% drawdown is brutal to live through.
Volatility (ann.) Standard deviation of daily returns, scaled to a year. Higher = more day-to-day swings. The Mag 7 typically sits around 25–35%; SPY runs 15–20%.
Sharpe Ratio Return per unit of risk (return ÷ volatility, no risk-free rate adjustment in this simplified version). Above 1 is good, above 2 is rare. Negative means you'd have been better off in cash.
Best / Worst Day The single biggest up-day and down-day in the window. Useful gut-check on tail risk.

Try these scenarios

"Did the Magnificent 7 actually beat the index?"

Click the Mag 7 (equal weight) preset, set lookback to 5 years, rebalance quarterly. Compare the orange line to the dashed SPY line. Note both the CAGR delta and the max drawdown delta — outperformance often comes with bigger swings.

"Concentrated bet vs. diversified?"

Run 100% NVDA over 5 years. Note the CAGR and the max drawdown. Then run 7-stock equal-weight Mag 7 over the same window. The single-stock bet usually has higher CAGR but a much uglier drawdown.

"Does rebalancing actually help?"

Run the same allocation twice — once with rebalancing off, once with quarterly rebalancing. Compare CAGR, max drawdown, and Sharpe. Rebalancing usually trims a bit of return but improves Sharpe (smoother ride).

"What if I'd DCA'd $500/month for 5 years?"

Set initial to $0 (or $500 for the first contribution), DCA to 500, lookback to 5 years. The chart will show steady upward steps from contributions in addition to market moves.

Caveats & data notes

How the data gets here: Chronoticker uses Yahoo Finance's public chart endpoint (no API key required) and routes requests through a small Netlify serverless function running on Netlify's edge. This sidesteps the CORS and rate-limiting problems that affect direct browser calls and public CORS proxies, and keeps the project fully keyless. If a request occasionally fails (Yahoo can still rate-limit), wait a few seconds and try again.

Educational use only. Backtests are a thinking tool, not a prediction. Past performance does not guarantee future results. Nothing here is financial advice.