Calculate Your Sports Betting ROI
Track your betting performance. Calculate ROI, units won, and whether you are actually profitable long-term.
What Is Betting ROI?
ROI (Return on Investment) measures your profit as a percentage of total money wagered. The formula: (Total Returns - Total Wagered) / Total Wagered × 100. A +5% ROI means you earn $5 for every $100 wagered over time. Professional sports bettors typically achieve +2% to +8% ROI over large sample sizes. Anything above +10% sustained is exceptional.
Sample Size Matters
Betting ROI is meaningless over small samples. Variance can make a losing bettor look brilliant over 50 bets, and a winning bettor look terrible. You need at least 500-1,000 bets at similar odds before ROI becomes statistically meaningful. At -110 odds with a true 53% win rate (+3.6% ROI), there is still a 25% chance of being negative after 200 bets purely due to variance.
The most successful bettors are not the best at picking winners — they are the best at finding value. A 55% win rate at -110 odds (7.3% ROI) is far more profitable than a 60% win rate at -200 odds (0% ROI). The relationship between win rate and odds determines profitability, not win rate alone.
