Making the Bet
Bankroll, Kelly, and discipline
You found an overlay. Now the question that busts more bettors than bad picks ever will: how much? Bet too big and one cold streak wipes you out before your edge can play out. Bet too small and you leave the edge on the table. The answer is to size every bet to how big the edge actually is.
Kelly sizes the bet to your edge: bigger edge → bigger bet. Full Kelly is the growth-optimal bet but swings hard, so pros bet a fraction (¼ here). Move the sliders to a negative edge and the correct stake is zero — discipline beats action.
Flat, then Kelly
Starting out, flat betting — the same small amount every play — is perfectly fine and keeps you out of trouble. As you trust your numbers, the Kelly criterion sizes each bet to its edge: more edge, more money. But full Kelly swings violently, so professionals bet a fraction of it (a quarter is common). Run the sim above a few times — same edge, totally different rides. That variance is why you stay small.
Paper until the gate opens
Every bet in this app is PAPER until the Harness returns EDGE with a holdout ROI whose confidence interval clears zero. That isn't a suggestion — it's enforced (the banner up top, the ROI gate on the Harness page). Paper betting builds the track record that earns live mode. Skipping it is how people set money on fire.
Win bets vs exotics
Win overlays are the bread and butter: simple, measurable, and where the cleanest edge lives. Exotics (exacta, trifecta, supers) are a different animal — high variance, big payoffs, best in chaos races where the favorites are vulnerable. They get their own scorecard and their own ROI, never mixed into your win results, because judging a lottery ticket by win rate is meaningless.