Definition
ROI (return on investment) in sports betting equals net profit divided by total amount risked, expressed as a percentage. ROI = (Total Winnings − Total Amount Wagered) ÷ Total Amount Wagered × 100. A 5% ROI means every $100 risked returns $105 on average. Industry benchmarks: 2–3% ROI over 500+ bets indicates skill; 5%+ is elite; recreational bettors average −4% to −8% ROI from vig alone. Always measure ROI over large sample sizes — short-run variance obscures signal.
Worked Example
200 bets, all $110 at −110. Total risked: $22,000. Won 112 bets (56%) × $100 = $11,200. Lost 88 bets × $110 = $9,680. Net profit: $11,200 − $9,680 = $1,520. ROI = $1,520 ÷ $22,000 = 6.9%. At 52.38% win rate (break-even): ROI = $0. At 50% win rate: ROI ≈ −4.5%.
Why It Matters
ROI normalizes across different bet sizes and time periods. Tracking units won is useful; tracking ROI on total risk tells you the true efficiency of your process.