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What is Expected Value (EV) in Betting?
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What is Expected Value (EV) in Betting?

Tom Hartley

Tom Hartley

6 min read

If there is one concept that separates long-term winning bettors from everyone else, it is expected value. Professional bettors do not think in terms of individual wins and losses. They think in terms of EV. Once you understand this idea, it changes how you approach every single bet you place.

What Is Expected Value?

Expected value (EV) tells you how much you can expect to win or lose on average per bet, if you were to place that same bet thousands of times. A bet with positive expected value (+EV) means you have a mathematical edge. A bet with negative expected value (-EV) means the bookmaker has the edge.

Most recreational bettors place -EV bets without realising it. The bookmaker's margin ensures that the average punter loses over time. The goal of a serious bettor is to consistently find and place +EV bets, because that is the only reliable path to long-term profit.

The EV Formula

The basic formula for expected value is:

EV = (Probability of Winning x Profit if You Win) - (Probability of Losing x Amount You Lose)

There is also a simpler percentage version:

EV% = (True Win Probability x Decimal Odds) - 1

If EV% is positive, the bet is +EV. If it is negative, the bet is -EV. If it is zero, you are breaking even.

Worked Example: Positive EV

You believe a football team has a 50% chance of winning. The bookmaker offers decimal odds of 2.20.

Using the formula:

EV% = (0.50 x 2.20) - 1 = 1.10 - 1 = +0.10 or +10%

This means for every 100 pounds you stake on bets like this, you would expect to profit 10 pounds on average over the long run. The bookmaker is offering odds that are too generous relative to the true probability, and that gap is your edge.

Worked Example: Negative EV

Now suppose the same team has a 50% chance of winning, but the bookmaker only offers odds of 1.85.

EV% = (0.50 x 1.85) - 1 = 0.925 - 1 = -0.075 or -7.5%

For every 100 pounds staked, you would expect to lose 7.50 on average. The bookmaker's odds are shorter than they should be, giving the house the edge. This is how most bookmakers make their money on every market they price.

Why EV Matters Long-Term

Individual bets are unpredictable. You can lose a +EV bet and win a -EV bet on any given day. But over hundreds and thousands of bets, the maths wins. A bettor consistently placing +EV bets will be profitable in the long run, even if they hit losing streaks along the way.

Think of it like a casino. The house does not win every hand of blackjack, but their mathematical edge ensures they profit over time. When you place +EV bets, you are playing the role of the house.

This is why professional bettors never judge their performance by a single bet or even a single week. They track EV% across thousands of bets and trust the process.

How to Find +EV Bets

Finding +EV bets requires two things: an accurate estimate of the true probability, and odds from a bookmaker that exceed what that probability implies. Here are the most reliable methods:

  • Use sharp bookmaker lines: Pinnacle is widely regarded as the sharpest bookmaker. Their closing odds are a strong proxy for true probability. If another bookmaker is offering higher odds than Pinnacle's closing line, that bet is likely +EV.
  • Compare across bookmakers: Odds vary between bookmakers due to different models, customer profiles, and risk management. Comparing odds across multiple firms helps you identify outliers that represent value.
  • Build your own models: Some bettors use statistical models to estimate probabilities independently. This takes time and skill, but it gives you an edge that is entirely your own.
  • Track closing line value: If you consistently beat the closing line (your odds at the time of placing were higher than the final odds before kick-off), it is strong evidence that your bets are +EV.

OddsNotifier's EV+ Scanner

Finding +EV bets manually across hundreds of bookmakers and thousands of markets is time-consuming. That is why OddsNotifier built the EV+ Scanner, which automates the process.

The EV+ Scanner compares odds from 250+ bookmakers against sharp reference lines to identify bets where the bookmaker's odds imply a lower probability than the true likelihood. It calculates the EV% for each opportunity and presents them in real time, so you can act before the odds move.

Rather than spending hours manually cross-referencing odds, the scanner does the heavy lifting and lets you focus on placing bets and managing your bankroll.

Common Misconceptions About EV

  • "I lost, so it was not +EV": A single result tells you nothing about EV. A coin flip bet at 2.10 odds is clearly +EV, but you will still lose roughly half the time.
  • "High odds mean high EV": EV depends on the relationship between odds and probability, not the size of the odds alone. A 1.50 bet can be +EV if the true probability is above 66.7%.
  • "I can feel when a bet is +EV": EV is a mathematical calculation, not an instinct. Without estimating the true probability, you cannot know whether a bet has positive or negative value.

Wrapping Up

Expected value is the foundation of profitable betting. Every serious bettor needs to understand it, calculate it, and use it to guide their decisions. Individual results will always be noisy, but +EV betting is the only approach that reliably generates profit over time.

If you want to skip the manual work and start finding +EV opportunities automatically, check out the EV+ Scanner. It analyses odds across 250+ bookmakers in real time and highlights the bets where the maths is on your side.