You can have a genuine edge and still go broke if you bet too large. Variance can knock out even profitable bettors who oversize. Proper sizing lets you survive the inevitable losing streaks while your edge plays out over hundreds of bets.
A unit is a fixed percentage of your bankroll — typically 1–2%. If your bankroll is $500, one unit is $5–$10. Thinking in units rather than dollars removes emotional attachment and makes your results comparable regardless of bankroll size.
BetIQ defaults to 1 unit = $10. You can change this in your account settings.
Kelly tells you exactly what fraction of your bankroll to bet to maximize long-run growth. Formula: Kelly % = (bp − q) ÷ b, where b = decimal profit on a win, p = win probability, q = loss probability.
Full Kelly is aggressive. BetIQ uses fractional Kelly (25% of full Kelly) — this sacrifices some growth rate for significantly less variance.
Simpler alternative: bet the same amount every time (1–2 units). Less optimal mathematically but much easier to stick to and still profitable if you have edge. Good starting point for new bettors.
Increasing bet size after losses (martingale, doubling down) is mathematically ruinous. It amplifies variance without improving your edge. Stick to your unit size regardless of recent results.