What is Expected Value in Sports Betting?

Expected Value Explained in Detail

Expected value is the single most important concept in sports betting. Every profitable bettor, whether they realize it or not, is making positive EV bets. The formula is: EV = (Probability of Winning x Amount Won per Bet) - (Probability of Losing x Amount Lost per Bet). If the result is positive, the bet has positive expected value.

Consider a bet at +150 odds where you estimate a 45% chance of winning. On a $100 bet, you win $150 profit 45% of the time and lose $100 55% of the time. EV = (0.45 x $150) - (0.55 x $100) = $67.50 - $55 = +$12.50. This bet has a positive EV of $12.50 per $100 wagered, making it a profitable bet over time.

The challenge is that expected value depends on your estimated probability being accurate. If you think a team has a 55% chance of winning but they actually have a 50% chance, what you calculated as a +EV bet is actually a -EV bet. This is why having accurate models and honest self-assessment of your edges is critical.

Expected value explains why you can lose a bet and still have made the right decision. If a +EV bet loses, you made the correct mathematical play, and you should make the same bet in the same situation next time. Conversely, winning a -EV bet does not make it a good bet. Process over results is the mindset of an EV-focused bettor.