How Do Horse Racing Odds Work? A Bookmaker Explains
If you're new to horse racing betting, understanding the odds can initially seem complicated. What does 5/2 mean? How much would a £10 bet at 8/1 return? What's the difference between fractional and decimal odds? And why do horse racing odds change before a race?
The principles are actually quite straightforward.
At Kevin Myles, we've been involved in racecourse bookmaking since 1989, taking bets at racecourses across Britain as well as providing betting services to customers away from the track.
In this guide, we'll explain how horse racing odds work, what the numbers mean, how to calculate potential winnings and why bookmakers' prices change.
What Are Horse Racing Odds?
Horse racing odds represent two things:
The potential return you could receive if your selection wins.
The bookmaker's assessment of the likelihood of that outcome.
In Britain, horse racing odds are traditionally displayed as fractional odds, such as:
2/1
5/2
4/1
8/1
10/1
You'll also increasingly see decimal odds, particularly when betting online.
Let's start with fractional odds because they're still synonymous with British horse racing.
How Do Fractional Horse Racing Odds Work?
Fractional odds tell you how much profit you could make relative to your stake.
Take 5/1.
For every £1 you stake, you could win £5 profit.
A £10 bet at 5/1 would therefore produce:
£50 winnings + your £10 stake returned = £60 total return.
Another example is 2/1.
A £10 win bet at 2/1 would produce:
£20 winnings + £10 stake = £30 total return.
The higher the odds, the larger the potential return – but generally the bookmaker considers the outcome less likely.
What Does 5/2 Mean in Horse Racing?
You'll frequently encounter prices that aren't whole numbers.
5/2 is a common example.
It means you could potentially win £5 for every £2 staked.
Therefore:
£2 at 5/2 = £5 profit + £2 stake = £7 return
£10 at 5/2 = £25 profit + £10 stake = £35 return
£20 at 5/2 = £50 profit + £20 stake = £70 return
The same principle applies to prices such as 7/2, 9/2 and 11/2.
What Does 6/4 Mean?
Odds can also be displayed with a larger denominator.
For example:
6/4
For every £4 staked, the potential profit is £6.
A £10 bet at 6/4 would therefore return:
£15 profit + £10 stake = £25 total return.
You may also hear 6/4 referred to as "six to four".
What Does Odds-On Mean?
Sometimes you'll see the fraction reversed:
4/5
4/6
1/2
These are known as odds-on prices.
With an odds-on selection, the potential profit is lower than the amount being staked.
For example:
A £10 bet at 1/2 would potentially produce £5 profit.
Your total return would therefore be:
£15
Odds-on prices generally indicate that the horse is considered to have a relatively strong chance of winning compared with horses available at larger prices.
What Is Evens?
Evens, sometimes displayed as EVS, essentially means 1/1.
You can potentially win the same amount as you stake.
So:
£10 at Evens = £10 profit + £10 stake = £20 return.
Horse Racing Odds Examples
Here's a simple guide to what a £10 win bet could return:
OddsPotential ProfitTotal Return1/2£5£15Evens£10£202/1£20£305/2£25£354/1£40£505/1£50£608/1£80£9010/1£100£11020/1£200£210
These examples assume a straightforward £10 win bet and don't account for deductions or other settlement rules that may apply in particular circumstances.
How Do Decimal Horse Racing Odds Work?
Decimal odds include the stake in the displayed potential return.
For example:
Fractional odds: 5/1
are equivalent to:
Decimal odds: 6.00
A £10 stake at decimal odds of 6.00 gives a potential total return of:
£10 × 6.00 = £60
Some other examples are:
FractionalDecimal1/21.50Evens2.002/13.005/23.504/15.005/16.0010/111.00
Many experienced British racing customers still prefer fractional odds, while decimal pricing makes calculating the total potential return particularly simple.
Why Do Horse Racing Odds Change?
One of the most interesting aspects of horse racing betting is that odds aren't necessarily fixed throughout the day.
A horse might be available at:
8/1 in the morning
then shorten to:
6/1
and eventually:
4/1
before the race.
Alternatively, its price could move in the opposite direction.
There are numerous reasons why horse racing odds move.
These can include the amount of money being wagered on individual horses, changes elsewhere in the betting market, new information, racing conditions and bookmakers adjusting their prices as the market develops.
This process becomes particularly visible at the racecourse as race time approaches.
How Do Racecourse Bookmakers Set Their Odds?
This is where horse racing becomes particularly interesting.
A racecourse betting ring is a live marketplace.
Bookmakers display prices for each horse and continually assess the market.
Prices can change as bets are taken and the market develops.
Bookmakers aren't simply trying to predict the winner. They are pricing the probability of the different outcomes while managing their betting book and responding to the wider market.
Having operated at British racecourses since 1989, Kevin Myles has experienced the enormous transformation of racecourse bookmaking, from the traditional betting ring to today's technology-driven markets.
The technology may have changed considerably, but understanding price, probability and the betting market remains fundamental to bookmaking.
What Does It Mean When a Horse Shortens in Price?
You'll often hear racing commentators say:
"The horse has shortened."
This simply means its odds have become smaller.
For example:
8/1 → 6/1 → 4/1
The potential return is getting smaller as the price shortens.
You'll sometimes hear this described as a horse being "backed" or "well backed", although price movements can happen for several reasons and don't guarantee that a horse will win.
What Does It Mean When a Horse Drifts?
The opposite of shortening is drifting.
For example:
3/1 → 4/1 → 5/1
The odds are getting larger.
This means someone placing a bet at the later price would potentially receive a larger return if the horse subsequently won.
Again, a drifting price doesn't tell you what will happen in the race.
What Is the Starting Price in Horse Racing?
Another term you'll encounter is the Starting Price, commonly abbreviated to SP.
The Starting Price is the industry-calculated price for each horse when the race begins.
If a qualifying bet is placed at SP rather than taking an available fixed price, the eventual return is calculated using that horse's official Starting Price, subject to the bookmaker's applicable rules.
We'll explain this in more detail in a separate Kevin Myles guide to Starting Price (SP) in horse racing.
How Do Each-Way Odds Work?
An each-way bet is effectively two bets:
one bet for the horse to win
and
one bet for the horse to place.
So a £10 each-way bet has a total stake of £20.
The place portion is settled at a fraction of the win odds according to the applicable place terms.
The number of places and fraction offered can depend on factors including the race type and number of runners, as well as the bookmaker's applicable terms.
Each-way betting deserves its own explanation, so we'll cover how each-way horse racing bets work in another guide.
Does the Favourite Always Win?
No.
The favourite is simply the horse with the shortest odds in the market at that point.
Being favourite doesn't guarantee victory.
Horse racing contains uncertainty – which is precisely why odds exist.
The price represents an assessment of probability, not a prediction of a certain result.
Understanding Probability and Horse Racing Odds
You can also convert odds into an approximate implied probability.
For example, decimal odds of 2.00 imply:
1 ÷ 2.00 = 50%
Decimal odds of 5.00 imply:
1 ÷ 5.00 = 20%
This doesn't mean a horse literally has exactly a 20% chance of winning. It's a useful mathematical representation of what that individual price implies before considering the construction of the overall bookmaker's market.
Understanding this relationship between odds and probability is one of the foundations of betting.
Horse Racing Betting Doesn't Have to Be Complicated
For someone encountering a betting ring or online racing market for the first time, a screen filled with fractions can look intimidating.
But remember the basic principle:
The odds determine the potential return on your stake.
If you're looking at 5/1, every £1 could potentially produce £5 profit.
Once you understand that, fractional horse racing odds become much easier to read.
About Kevin Myles
Kevin Myles is an independent British bookmaker with racecourse bookmaking experience dating back to 1989.
From the traditional racecourse betting ring to modern online betting, the business has evolved alongside the British betting industry while maintaining its connection with racecourse bookmaking.
You can learn more about Kevin Myles, our racecourse operations and betting services throughout KevinMyles.co.uk.
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