What is a Sure bet?

A Sure bet, or arbitrage bet, is a system of betting that involves exploiting differences in odds between different bookmakers. The differential in odds arises from differing opinions on the outcome of events between bookmakers or, sometimes, errors on the part of the bookmaker. A sure bet works by placing two bets, one for and one against a particular outcome with two different bookmakers. When done correctly the bet is guaranteed to make a profit. Bookmakers typically frown on this behavior and attempt to guard themselves from it, but the practice is 100% legal and wide spread in its practice. The emergence of online bookmakers, software tools and online betting services has made sure bets easier and profitable.

How Sure bets Work

A bookmaker will never post odds where the sum of the inverse of all possible outcomes is less than 1. This mathematical fact ensures their profit margin. Looking for a sure bet, then, requires finding two bookmakers such that the inverse of the odds of one outcome with one bookmaker added to the inverse of the odds of the other outcome with another bookmaker is less than 1. This ensures the sure bet is profitable, that’s how the math works. Additionally the bets need to be in the proper amounts. Once a sure bet opportunity is found, the first bet needs to be placed and the second bet needs to be of the amount: (first bet amount) * (bookmaker 1 odds for outcome 1) / (bookmaker 2 odds for outcome 2). In practice if two different bookmakers were giving 3/1 odds and 2/1 odds on the same event and a bettor placed a covering bet of $500 and $333 respectively, the bettor would be sure of receiving $1000 at a cost of $833.


Maximizing Signup Bonuses with Sure bets

Some online bookmakers will give a small amount of cash to new users to be used in placing bets. Most of this virtual currency is required to be used in several bets before it can be cashed out, however, thus the bookmaker gives themselves the chance to win that ‘bonus’ money back from the user. Using a series of sure bets, the better can mitigate or negate possible losses over the course of several bets and cash out the bonus money. Of course this system only works one time per bookmaker, since the bonus is only for new users, but by creating new accounts with multiple bookmakers it is a quick way to boost profits by using surebets as long as the bookmakers offer a signup bonus.

Back-Lay betting using a Betting Exchange

In traditional betting, a bettor will bet (back) a particular outcome and the house will bet against that outcome (a lay). Betting exchanges have arisen where a neutral party (the exchange) facilitates betting between customers who have the opportunity to both back and lay on the same event. This creates opportunities for a sure bet all in one venue. As an added feature, betting exchanges give the opportunity of trading bets; that is, placing bets at a time when they may not be profitable in the hopes that a more profitable opportunity will arise at a later time. Betting exchanges offer this neutral service for a small fee per bet, the exactly how a stock exchange operates. These fees need to be considered and accounted for when performing the calculations for a sure bet.


Fraud: Practicing sure bet bets requires a high volume of accounts with different online bookmakers. Each one of these accounts contains personal information for contact and payout, everything from name and address to credit card information. Due to this, betters practicing sure bets are more susceptible to hacking, social engineering and fraud than normal betters who know how to bet through one or two sites.

Human error: As seen above in the example of how a sure bet works, the math is fairly complex and the payoff is often small, profits ranging from 2% to 4%. This leaves very little margin for error when it comes to placing bets at the correct odds and for the correct amounts.

Bet cancelations: There are situations where a bookmaker is allowed to cancel a bet. If one half of a surebet is canceled, then the remaining half is becomes a normal bet.

Equalized sure bet opportunities. Surebet betting is like a trading house, with bookmakers the markets and the odds the prices of commodities. During the natural course of betting, the odds will average out across different bookmakers and surebet opportunities will vanish. The average time window for a sure bet opportunity is 15 minutes, so it is possible that by the time the first half of the bet is set up, the opportunity has vanished and the sure bet has turned into a normal bet.


When sure bets are placed correctly, in large volumes and with large enough sums of money they can be very profitable. Using software to identify surebet opportunities and to calculate the amounts needed, the risk can be brought to a very low level. Someone taking advantage of surebet opportunities still needs an understanding of betting systems and enough time and dedication to place the volume of bets required, but otherwise the cost of entry is very low. If you have the time, the money and hate losing when placing bets, then surebets is likely the way to go.

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Author Information

Thomas Singer
I'm Thomas Singer, freelance journalist at the Berliner Zeitung and a professional sports bettor. During my study of sports science at the Humboldt University in Berlin I discovered my passion for sports betting and optimized my system so that I can practice both as a journalists and my hobby. I'm happy about every new follower on my Google+ profile.