Backtest Lab
Settle the debate with real data
Feed the same monthly cash into two strategies — invest it right away, or wait for a dip — and see which ends up with more, across every start date since the 1990s.
What you can do
1
Fair comparison
Same money, same dates — only the timing of the buys differs.
2
Your dip rules
Drawdown from a high, a one-day drop or a gap below a moving average.
3
Rolling windows
Hundreds of start dates, so one lucky period can't fool you.
4
Saved scenarios
Keep every variant on your account and come back to tweak it.
How it works
- Step 1
Pick a ticker
SPY by default — any Yahoo symbol works.
- Step 2
Set the rules
How much you invest, how often, and what counts as a dip.
- Step 3
Compare & save
Read the verdict, test the alternatives, save what you learn.