How To Understand Betting Odds

The odds of an event happening is the likelihood or probability of that result. Odds are at the centre of all betting, whether sporting or otherwise, so before placing a bet on anything you should understand odds and how they work.

Our betting odds guide will give you an understanding of betting odds, so you can work out how likely you are to win and what you will win if the result goes your way.

Find out more today about betting odds:

How To Understand Betting Odds

What Are Betting Odds?

Betting odds represent how likely an event is to happen.

They are set by bookmakers on a full variety of events from footfall, tennis, horse racing events, rugby, politics, X-factor results and more.

It is considered that:

  • The shorter the odds the more likely of outcome (however, the punter will win less)
  • The longer the odds the more unlikely that outcome is considered (but the punter will win more).

In the UK bettings, odds are typically displayed in a fractional format, for example, 3-1 (or three to one chance). This means that the likelihood of that outcome is one in every three times.

As well as the likelihood or probability of an event occurring, these gambling odds represent the ratio between your stake wagered vs the betting returns that the online bookmaker or betting shop will pay for the event to happen. So in the example of 3-1, you will get 3 times your money returned.

When trying to figure out what you have won from a racing bet you should use our free and easy betting calculator, it works out exactly what you can expect back – quickly and easily.

Odds Conversion Table

Fraction Odds Decimal Odds American Probability
1/100 1.01 -10000 99%
1/5 1.2 -500 83.30%
2/9 1.22 -450 81.80%
1/4 1.25 -400 80%
2/7 1.29 -350 77.80%
3/10 1.3 -333.3 76.90%
1/3 1.33 -300 75%
4/11 1.36 -275 73.30%
2/5 1.4 -250 71.40%
4/9 1.44 -225 69.20%
1/2 1.5 -200 66.70%
8/15 1.53 -187.5 65.20%
4/7 1.57 -175 63.60%
8/13 1.62 -162.5 61.90%
4/6 1.67 -150 60%
8/11 1.73 -137.5 57.90%
4/5 1.8 -125 55.60%
5/6 1.83 -120 54.50%
10/11 1.91 -110 52.40%
1/1 2 100 50%
21/20 2.05 105 48.80%
11/10 2.1 110 47.60%
23/20 2.15 115 46.50%
6/5 2.2 120 45.50%
5/4 2.25 125 44.40%
11/8 2.38 137.5 42.10%
7/5 2.4 140 41.70%
6/4 2.5 150 40%
8/5 2.6 160 38.50%
13/8 2.62 162.5 38.10%
7/4 2.75 175 36.40%
9/5 2.8 180 35.70%
15/8 2.88 187.5 34.80%
2/1 3 200 33.30%
11/5 3.2 220 31.20%
9/4 3.25 225 30.80%
12/5 3.4 240 29.40%
5/2 3.5 250 28.60%
13/5 3.6 260 27.80%
11/4 3.75 275 26.70%
3/1 4 300 25%
16/5 4.2 320 23.80%
10/3 4.33 333.3 23.10%
7/2 4.5 350 22.20%
4/1 5 400 20%
9/2 5.5 450 18.20%
5/1 6 500 16.70%
11/2 6.5 550 15.40%
6/1 7 600 14.30%
13/2 7.5 650 13.30%
7/1 8 700 12.50%
15/2 8.5 750 11.80%
8/1 9 800 11.10%
9/1 10 900 10%
10/1 11 1000 9.10%
11/1 12 1100 8.30%
12/1 13 1200 7.70%
13/1 14 1300 7.10%
14/1 15 1400 6.70%
15/1 16 1500 6.20%
16/1 17 1600 5.90%
18/1 19 1800 5.30%
20/1 21 2000 4.80%
25/1 26 2500 3.80%
33/1 34 3300 2.90%
50/1 51 5000 2%
66/1 67 6600 1.50%
100/1 101 10000 1%
1000/1 1001 100000 0.10%

What is Probability?

Probability is how likely something is expected to happen, probability then dictates what odds are.

If a bookmaker believes the outcome of an event has a high probability of happening – meaning that it is more likely to happen than not – odds will be shorter, so a punter can less money.

If the event happening is deemed to have a low probability – then it’s less likely to happen than not – odds will be bigger.

A very simple example of probability in action is probably when tossing a coin, where there are two outcomes (heads or tails). You have the same statistical chance of getting either; the chance of getting either is 1 out of 2. This is represented as a 50% chance and in odds is 1/1 (evens) – as you have an even chance of getting either.

What Are Fractional Odds?

Fractional odds are the oldest forms of odds for horse racing and they are still the preferred format used in the UK in shops and on UK racecourses.

Fractional odds are simple to calculate because they are given in fraction form. The denominator (or 2nd number) to the right is the amount bet and the numerator or 1st number (on the left) is the amount that your bet will return.

Fractional Odds Examples

Here are some fractional odds examples showing what you would win:

  • 7/1 for every £1 you bet, you will win £7
  • 5/2 for every £2 you bet, you will win £5
  • 11/4 for every £4 you bet, you will win £11
  • 1/1 for every £250 you bet, you will win £250

What Are Decimal Odds?

Decimal odds (they are sometimes known as European odds or American odds) are popular because of their simplicity.

This odds type is shown as two figures which are separated by a full stop. For example 1.2o, 1.70, 2.30 or 6.4. Decimal odds are arguably easy to work out as you as you just times your stake by the relevant odds.

Decimal Odds Examples

Here are some decimal odds examples showing what you would win:

  • 4.5 can be calculated as (4.5 * £100 stake) – £100 stake = £350 winnings
  • 1.3 can be calculated as (1.3 * £500 stake) – £500 stake = £150 winnings
  • 9.2 can be calculated as (9.2 * £10 stake) – £10 stake = £82 winnings
  • 2.5 can be calculated as (2.5 * £200 stake) – £200 stake = £300 winnings

Decimal Odds vs Fractional Odds – Key Facts

Here are some facts to consider when choosing your odds format for betting:

  • Fractional odds are the ratio of the profit won to the stake wagered
  • Decimal odds represent the amount you win for every £1 wagered on your betting slip
  • The fractional odds only represent winnings and do not include your returned stake
  • The decimal odds do include the stake within the odds stated
  • UK racecourses and Irish Racecourses generally show prices in fractional odds, where decimal odds are known to be more American and European
  • With the growth of Betfair exchange in the UK, many punters become familiar with the decimal odds platform.

Summary of Betting Odds Overview

The choice of decimal odds or fractional odds all comes down to personal preference, all the best horse racing betting sites and best betting app options, allow you to choose which you would prefer to show when making your betting selections.

As betting odds represent the probability of an event to happen it is up to the punter to try and find value for money by seeing if they agree with the odds being offered by a bookmaker and if these odds represent a good betting option.

If you are looking to place a bet – firstly always remember to bet responsibly – but do check out our recommended bookies below:

Some of the above bookies offer free bets and great sign-up perks, as well as betting on horses, Premier League betting and other sports betting options.

Odds Used in the Betting Market

Here is a list of guides for specific betting odds used by UK sportsbook bookmakers:

As the Founder of British Racecourses, I have a life-long passion for horse racing and have loved the sport as long as I can remember. I am also a keen racehorse owner and have worked in the gambling industry for several years. I set up British Racecourses with the desire to share my passion for racing with other like-minded people.