What is Overround Betting?

Overround betting is how a sportsbook makes a profit on bets it takes. For each bet, a sportsbook will offer odds with implied odds of over 100%. The percentage points above 100 are the profit level the sportsbook is taking. So, if the implied odds from all betting options total 107%, there’s an overround of 7%.

An example of this could be a soccer game. If it’s a tight game, the odds for a home win, an away win, or a draw will all be similar. So you may see the odds as follows:

Home: 2.50

Away: 3.00

Draw: 3.00

In this situation, the home team has an implied probability of 40% to win, the away team has an implied probability of 33.3% to win, and a draw would have an implied probability of 33.3%. So, it gives an overall implied probability of 106.67%. So, the sportsbook has a profit margin of 6.67%.

It means whatever choices bettors make, the profit margin ensures the sportsbook is likely to make a profit. Of course, if all bettors choose a single choice and it wins, the sportsbook will make a loss. But the concept of overround betting means the sportsbook expects bettors to place an even spread of bets.

Crypto bookmakers will use the probability of events to create the odds for their games. The sportsbook will use these odds to calculate the overround. In some circumstances, the odds and probability won’t match up perfectly. It’s through this method players can find value for bets.

How to Use the Calculator

  • The “Selection” column is optional and does not affect the calculation.
  • Choose your preferred odds format; decimal, fractional or American.
  • The odds for all possible outcomes must be included.

With the above calculator, you can work out the book % and sportsbook’s overround for any betting market. This means you can check if a sportsbook is giving you good value odds and you can check whether arbitrage opportunities exist across different sportsbooks.

How Much Overround Should There Be?

The below table is for 2 selection betting markets. It’s normal for the overround to rise as the number of selections rise, because some overround has to be added to the odds of each selection.

Overround Value
Negative Arbitrage bet on all selections for guaranteed profit!
0% – 3.5% Competitive good value odds
3.5% – 5% Acceptable odds
5%-7% Poor value odds, look elsewhere
Greater than 7% A rip-off!

It is almost impossible to make long term profit if your sportsbook gives you odds with more than a 5% overround. See our best odds sportsbook rankings to find out if that is the case with your sportsbook.

How Does a Bookie Achieve Overround?

Of course, it would be bettors if every event had a negative overround. However, the fact remains crypto bookies are a business. They are aiming to make a profit. So, there’s no way bookies would exist without overround. While it may seem unfair to some players, overround is vital for bettors. There’s also the fun of finding good value and beating the bookies using skill and research.

Sportsbooks use the probability of an event to set their odds. Each event has different factors which contribute to setting the odds. Injuries, current form, respective position in the standings, which team is home or away, and anything else which can impact the result. After deciding on the probability, the sportsbook will use it to set the odds.

Each event will have various odds depending on who is playing and the other respective factors. As such, the overround for each event will differ. Players should calculate the overround for each bet to ensure they are getting the best possible value.

How Can You Use Overround for Arbitrage Betting?

Arbitrage betting is the act of placing wagers which guarantee a win. It can be through different promotions the crypto sportsbook offers or through different crypto sportsbooks. It’s the second option which provides players with the opportunity to carry out arbitrage betting with overround.

Using the overround at different crypto betting sites ensures players can find events with varying odds. So, it allows for arbitrage betting to take place. The primary premise players must look for is an overround below 100%. In this situation, it means there is an opportunity for players to make a profit. Of course, the overround is unlikely to be below 100% at a single sportsbook, but it is possible when combining sportsbooks.

So, if the Lakers and Warriors are playing, players may want to look at different sportsbooks to calculate the overround.

  • Sportsbook A could offer 2.50 on the Warriors and 1.60 on the Lakers
  • Sportsbook B could offer 1.80 on the Warriors and 2.20 on the Lakers

In this situation, betting 1 BTC on the Warriors at sportsbook A and 1 BTC on the Lakers at sportsbook B would guarantee a profit. If the Warriors win, it would be a 2 BTC outlay for a return of 2.5 BTC. If the Lakers win, it would be a 2 BTC outlay for a return of 2.2 BTC. So, players have a guarantee of at least 0.2 BTC profit.

Of course, finding overround disparity like this isn’t simple. It requires a lot of research for players to discover events where this is the case. Primarily as many crypto sportsbooks use the same stats to calculate the probability for an event and, therefore, their odds. However, when sportsbooks are running promotions, it can make it an easier task to find arbitrage.

Potential Risks

There are risks when using overround to find arbitrage betting opportunities. Some crypto sportsbooks look down on this practice. If they discover players have bet at multiple sportsbooks to place arbitrage bets, there is a chance they will cancel bets. It can also lead to odds changes from sportsbooks, which can further ruin opportunities.

Finally, the most significant risk is if the crypto sportsbooks don’t allow arbitrage betting in its terms and conditions. In this situation, it can lead to players losing their accounts. So, it’s essential to be careful when arbitrage betting.

Overround of 50/50 odds

A 50/50 bet has an equal chance of winning or losing. Totals and spreads are often 50/50 markets. If there was no overround the odds would be 2. Below is the overround for different 50/50 odds.

Decimal Fractional American Overround
2 1/1 +/-100 0%
1.99 1/1 -101 0.50%
1.98 1/1 -102 1.01%
1.97 20/21 -103 1.52%
1.96 20/21 -104 2.04%
1.95 20/21 -105 2.56%
1.94 20/21 -106 3.09%
1.93 10/11 -108 3.63%
1.92 10/11 -109 4.17%
1.91 10/11 -110 4.71%
1.9 9/10 -111 5.26%
1.89 9/10 -112 5.82%
1.88 9/10 -114 6.38%
1.87 9/10 -115 6.95%
1.86 5/6 -116 7.53%
1.85 5/6 -118 8.11%
1.84 5/6 -119 8.70%
1.83 5/6 -120 9.29%
1.82 5/6 -122 9.89%
1.81 4/5 -123 10.50%
1.8 4/5 -125 11.11%


Overrround is unavoidable when playing at a crypto sportsbook. As such, players must understand how to use it to their advantage. With each sportsbook putting its overround on every bet, each bet has a profit margin. However, with our overround calculator, players can find the best value bets on the market. By combining sportsbooks there is also the possibility of finding guaranteed wins. However, players should be aware of the risks this brings.

Whether players want to find good value bets or carry out arbitrage betting, our calculator is a vital tool. It makes it easier to find the best value overall bets. For low-risk bettors, knowing which bets provide the lowest risk and the highest value is essential. Any bettor who looks to make a long-term profit should use our calculator to increase their chances.

Overround is a vital concept to understand when betting, so our overround calculator ensures players can go into each bet with their eyes open.


Bookies need the overround to ensure a profit margin on each bet they offer. Without the overround, players could theoretically make a profit on every bet they place. In this situation, it would lead to the bookie going out of business. Of course, this would be a negative for bettors as they no longer have a sportsbook available.

It is possible to avoid the overround. However, it’s unlikely this is possible in a single sportsbook. Players must use multiple sportsbooks to avoid the overround. There’s also no guarantee it will be possible at each event.

The payout is how much a bet returns to players. It’s essential to understand this isn’t the same as the profit. The payout will include the initial stake for the bet. So, to calculate their profit, players must subtract their stake from the payout.

18+ only. Gambling can be addictive, please play responsibly.
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Will Wood

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I first started writing professionally in 2015 about different areas of the online gambling world, quickly becoming an expert in everything from video slots to playing perfect Blackjack. My whole world changed in 2016 when I discovered a Bitcoin faucet. As I discovered more about crypto, the crypto gambling world appealed to me due to combining two of my passions.

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Will Wood


Updated on 21/02/2024