Arbitrage Calculator

This arb calculator works out the optimal stakes to place on both outcomes of a two outcome event to lock in a profit. Two outcome events that have good arb potential include tennis and darts where a draw is not possible. Either one player wins, or the other player wins. Just enter the odds of each player along with the total amount you would like to stake and the calculator will tell you how much to stake on each player.

Arbitrage is the act of exploiting price discrepancies by placing transactions in two or more markets in order to lock in a profit.

In the case of tennis, or any other two outcome event, it is possible to make a profit by backing both players to win. We can think of the odds available for player 1 as one market and the odds for player 2 as another market. This matches the definition of arbitrage that requires two or more markets.

For example, Rafael Nadal might be playing Roger Federer in the Wimbledon final. This match cannot end in a draw. Rafael Nadal is priced at 1.50 with one bookmaker and Roger Federer is priced at 3.5 with another bookmaker. Let's say we have £10 we would like to bet on this match.

If Rafael Nadal wins our account is as follows:

If Roger Feder wins our accounts is as follows:

It doesn't matter who wins the match, a profit of £0.50 is made by placing carefully sized transactions, or bets, in two different markets.

Many bookmakers cover sports in-running. This means the odds change frequently on both players during the event. Often this results in the opportunity to arbitrage your bets because each bookmaker uses slightly different information, algorithms and tools to set their prices.

In the example arb above, it didn't matter who won the tennis match, the same profit of £0.50 was made. That is not the only way to take advantage of arbing though. For example, maybe you have watched all of Nadal's matches on the way to the final and you think he is starting to run out of energy and you think Federer is more likely to win, but you don't want to lose any money on the bet.

In this case you could bias your arb bet towards Feder as follows:

If Rafael Nadal wins our account is as follows:

If Roger Feder wins our accounts is as follows:

If you are wrong and Nadal wins then you break even as the Nadal bet returns £10, which matches our original stake. But if you are right and Federer wins then you make a profit of £1.66 because you calculated your arb bet stakes with a bias towards Federer.

Arbitrage bets can occur before an event starts or after it has gone in-running. Before an event has started there are several factors that can cause arbs such as difference of opinion between bookmakers; different bonuses being offered by different bookmakers; bookmakers trying to adjust their exposure after taking a lot of money on one side of a market but not the other.

Arbs that arise before an event starts tend to disappear pretty quickly. This is because arb hunters will quickly find them and poor more money into the market to take advantage of the arc. Once enough money has exploited the arb the prices will tend to change and the arb opportunity will no longer exist.

As far as sports betting is concerned you can make an arbitrage bet with any pair of bookmakers offering equivalent markets on the same two outcome event. Betting exchanges can also be used when placing arbitrage bets.

It is reasonable to ask why, if arbs give the public a chance to make a risk free profit, do the bookmakers offer odds that create arb opportunities? The answer is that each bookmaker prices their own markets independently. If you only ever look at prices from a single bookmaker you will never find an arb opportunity. This is because a bookmaker ensures that the prices in their own markets are such that it is not possible to bet on each outcome and make a profit.

When you look across different bookmakers, who are all using slightly different information and tools to determine the odds they will offer, this is where discrepancies arise. In-running betting markets tend to have more arb opportunities because the reactions to certain key events such as winning a point, losing a set, breaking a serve are often over reactions, causing larger swings in odds.

If you intend to use a betting exchange to place arb bets you need to consider commission. If your winning bet is the one placed with the betting exchange they will deduct a commission from your profit on that bet, and this can change the overall profitability of your arb. Sometimes commission can turn a profitable arb into a losing arb, so always take this into account.

Unless you have some arb software to automatically find arbs for you, it can be helpful to recognise some common breakeven price points around which arb opportunities start to emerge.

Very often, by the time you have spotted an arbitrage opportunity and worked out which stakes to place, the opportunity may have gone away. Or you may find that you place one half of the bet and the odds have changed against you before you can get the second bet placed. Things can and will go wrong for you from time to time, so don't bet more than you are prepared to lose.

These are some of the risks you need to overcome when placing arb bets:

• Timing - you place one bet and the odds change before you can place the second bet
• Liquidity/betting limits - not all bookmakers and exchanges will allow you place the same size bet, so consider whether your stake size is viable before making your arb