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Betting Odds Questions

Our betting odds page gives a full list of betting odds in fractional, decimal and percentage (‘chance’) formats but what does these different odds formats mean to your bets? Here we try to explain what they mean and how they affect your bets.

What are odds?
Odds, in betting terms, are a reflection of the bookmakers opinion on the probability or chance of an even occurring. Any event, no matter how common or how rare, has a chance of occuring. Bookmakers employ experts in given fields to analyse the probability of each event, form a market and convert each probability into betting odds.

What is probability in betting?
Probability is the ‘chance’ that something will happen, an outcome will occur. The most obvious probability that everybody is aware of is the toss of a coin, there is a 50% chance of a head and a 50% chance of a tail….assuming a fair coin! If five identical people ran in a race then each person would have a 20% chance of winning. In every case all possible outcomes should total 100%.

Bookmakers take the probabilities for an event, totalling 100%, and then work in a profit for themselves, known as margin, by manipulating the prices that they offer. We will detail how this works below with our two examples above.

What are fractional odds in betting?
For every given probability expressed as a percentage, 50%, there is a corresponding fractional price available, Evens (1/1), these are detailed in our betting odds page. Any probability, whether expressed as a percentage, fractional or decimal means the same thing. In the coin toss you have a 50% chance of being correct and a bet placed at even money, or 1/1, would imply that ‘you should’ lose once and win once. Obviously this doesn’t always work on a toss-per-toss basis but over a large number will level out to 50%.

In our five runner race a chance of 20% would equate to a fractional price of 4/1, which implies you will pick the correct outcome once in five events and be paid four times your stake unit plus your stake unit returned. e.g. a £10 bet at 4/1 on our race would return £50.00 if correct.

What are decimal odds in betting?
Decimal odds can be calculated by taking the chance of an event occurring and dividing 100 by it. Unlike fractional odds the prices quoted in decimal odds include the original stake unit.

For our coin toss each outcome has a 50% chance, this gives decimal odds of 2.00 (100/50), a £10 bet on a correct result would give a return of £20.00.
In our five runner race each outcome has a 20% chance, this give decimal odds of 5.00 (100/20), a £10 bet on a correct result would give a return of £50.00

How does a bookmaker’s margin work?
In the two events above the odds quoted are true odds, the market is formed to 100%. For a bookmaker to lock in a profit (margin) they manipulate the true odds of an event downwards, thereby offering less value to a customer. Think of this like a shopkeeper increasing prices to make more profit.

In our race above each runner would be 4/1 (5.00) but a bookmaker might offer a price of 7/2 (4.50) on each selection. This would mean that over five races if one bet was placed each time on one selection a total of £50.00 will have been staked and, if probability works correctly, only one bet should win with a payout of £45.00, giving a profit of £5.00 to the bookmaker.

What is value in betting?
Value in betting occurs when the customer is placing a bet at a price BETTER than the true price of the event occurring. In our race example if a bookmaker was to offer 5/1 instead of 4/1 then this would be good value, the customer could bet over the five events spending £50.00 and one winner would give a return of £60.00. If you can get value on a bet then you should ALWAYS place the bet, over the long term this will guarantee a profit!

Bookmakers work hard to guarantee that their information is sound and prices correct. Value is not always easy to find in betting markets!

What is odds against?
Odds against is any price GREATER than Evens (2.00) and will result in a return more than double the original stake. In our race example 4/1 is odds against.

What is even money?
Even money (Evens, 1/1, 2.00) are the odds offered on a 50/50 outcome and will result in a payout of exactly double your money if correct.

What is odds on?
Odds on is any price LESS than Evens (2.00) and will result in a return less than double the original stake. An example of odds which are odds on is 1/4, in which you would have to stake £4 to win £1, total return £5. Sometimes this price would be referred to as 4/1 ‘on’, which means it is odds on and the odds are reversed.