![Betting odds explained: guide to how betting odds work](/https/www.telegraph.co.uk/content/dam/betting/Better-Collective/Betting_Explained.jpg?imwidth=680)
Betting odds explained: guide to how betting odds work
How odds work is one of the more popular questions asked by newcomers to gambling and all bettors should know the answer
![Betting odds explained: guide to how betting odds work](/https/www.telegraph.co.uk/content/dam/betting/Better-Collective/Betting_Explained.jpg?imwidth=680)
Knowing how to understand and calculate odds is something that anyone who is placing bets should take the time to learn. The odds reflect your selection’s chance of winning in the eyes of the bookmakers and how much money you stand to win if your wager is successful.
Although betting odds can look confusing at first, our complete guide will make sure you have the knowledge of how they work and can make more informed choices when gambling online.
What are betting odds?
Betting odds are compiled by bookmakers as a way to represent what they believe is the likelihood is of an event or events happening.
These odds are usually represented as either a fraction (2/1) or a decimal (3.0), which is used in the UK and around Europe. There’s also the moneyline or American way, which is where a number has a plus or minus in front of it (+200).
Betting odds are applied to any event that bookmakers are taking bets on, from horse racing and football to TV specials and politics.
Already used the bet365 bonus code? Check out all the latest bookmaker offers and the best betting sites.
What is probability?
Probability is simply how likely something is to happen. If the bookmaker has an outcome to an event with a high probability, then it’s more likely to happen than not. If the event is deemed to have a low probability, then it’s less likely to happen than not.
Probability is most commonly shown as a fraction by UK bookmakers, and would be two numbers separated by a forward slash (e.g. 1/2).
A very simple explanation of probability would be a coin toss, in which the two possible outcomes are heads or tails. The probability of getting heads is a one in two chance, which can be represented as odds of 1/1, which would mean the outcome has a 50% chance of winning. This is how punters can use the betting odds to work out how likely bookmakers believe an outcome is to happen.
How to calculate probability from betting odds
Now you know odds are set out with two numbers separated by a forward slash, you can use them to work out the probability of an event happening.
The method for calculating probability (in percentage terms) from odds is most easily explained by taking the two numbers that appear in the odds and replacing them with letters. So, for example 2/1 becomes A/B. The calculation is: Probability (%) = B/(A+B).
Here are some examples of betting odds converted into percentages to find out the probability.
How to read betting odds
Now you know how to work out the probability of an event happening, you can use the betting odds to work out the potential returns if you were to bet on it.
Fractional odds tell you the potential winnings in relation to the stake you place on the bet. For example, if you place a £1 bet on West Ham to beat Tottenham at 4/1, it will pay out £5 if successful (£4 profit plus your £1 stake). See below for more examples of how to read betting odds.
Any odds in which the first number is bigger than the second are odds against, while any odds in which the first number is smaller than the second are odds on. Odds-on events are considered more likely to happen than not by bookmakers, and vice versa for events that odds against.
How decimal odds work
When converted into decimals, the potential winnings include the stake, so you just multiply the stake by the odds. Decimal odds are often used on betting exchanges, such as Betfair, as the user is in control of the odds rather than the bookmaker. Here are some examples of how to read decimal betting odds.
- 11.00 odds = £1 bet would return £11 including stake
- 4.5 odds = £1 bet would return £4.50 including stake
- 1.5 odds = £1 bet would return £1.50 including stake
How American odds work
Although fractional and decimal betting odds are the most common way a bookmaker showcases their prices on an event, it’s still handy to know how the moneyline or American version works.
Let’s return to the coin toss example, in which the odds for heads and tails are both even money or 1/1 (fractional) or 2.0 (decimal), meaning that a £1 stake will return £2 (£1 profit plus the £1 stake).
In American or moneyline odds the heads and tails outcomes would be expressed as -100 or +100. And 100 is the key number, which we will illustrate with another example. This time it’s an American football match and the American/moneyline odds are as follows:
- New England Patriots @ -145
- Miami Dolphins @ +130
If you think Miami Dolphins will win, the +130 means that for every £100 you stake on them, you will win £230 (£130 plus your £100 stake). A £10 bet would mean you will win £23 – your £10 stake and £13 profit (calculated as £10/£100 x 130).
The minus in front of the New England Patriots odds means they are favourites and the calculation is different. The -145 means you will win £100 for every £145 you stake. So, if you were to place a £10 bet it would return £16.90 – your £10 stake and £6.90 profit (calculated as £10/£145 x 100).
In both examples for the £10 stake the calculation is:
(actual stake/American odds stake) x American odds winnings.
How odds work summary
That’s our full rundown on how betting odds work, so now you will know how to read odds, what the probability of a bet winning is according to the odds and what your potential winnings are.
Now you’re ready to start betting, and if you want to open an account with a bookmaker, you should take advantage of the incredible new customer offers available on the Telegraph’s free bets page.
Fractional odds tell you the potential winnings in relation to the stake you place on the bet. For example, if you place a £1 bet on West Ham to beat Tottenham at 4/1, it will pay out £5 if successful (£4 profit plus your £1 stake). See below for more examples of how to read betting odds.