What Does Odds On Mean in Betting?

For newcomers to sports betting, odds can be a confusing topic to get your head around.

These fractions (or decimals if you’re in Europe) essentially showcase how likely the bookmakers think something is to happen, with a little profit margin built in on top to help protect them from major losses… but that last bit is a whole other topic for another day.

Generally, bets can be considered odds-on or odds-against, which again sounds complex but is very simple to understand when you get your head around.

Odds-On Definition

When the bookies believe something is very likely to happen, they will make their odds so short that each punter that places a winning bet on that outcome will only make a small fraction of their stake as profit.

This would be an odds on bet, and the easiest visual clue is where the number on the left of the fraction is smaller than the number on the right – prices like 1/6, 1/2, 4/5, 8/11 and so on are all examples of odds-on betting.

If you placed a bet on a horse at 1/10 and it won, you would win £1 for every £10 placed. Not always the most profitable venture in the long run…

To help you understand further, an odds-against bet is one from which you will more than double your money if your selection wins. For instance, a winning £10 wager at odds of 3/1 will return £40 – your stake back and £30 earnings on top.

The secret to successful sports betting, whether you take an odds-on price or odds against, is to only wager on outcomes you believe have a greater chance of occurring than the odds given by the bookmakers.

How are Betting Odds Decided?

Bookmakers employ some of the sharpest analytical minds and the latest software tools to model how they think a sporting contest will play out.

For the most popular betting heats, they will even run thousands of simulations to see what the true likelihood of each outcome occurring is, before setting their odds accordingly – their prices reflect the ‘implied probability’ of a football team scoring, for example, or a racehorse winning.

The shorter the odds, the higher the probability of the thing happening – that’s the golden rule.

Naturally, odds-on selections have a higher probability of occurring. A 1/10 shot, for instance, has an implied probability of around 91%. In contrast, a 10/1 chance is given a probability of just 9%.

It should be noted at this point that odds can change. Sometimes a selection will drift in price, i.e. its odds grow longer and therefore so too does the implied probability of it happening. The opposite is true when the odds shorten.

There are numerous reasons that odds change before the game/race/tournament starts, whether its changing conditions (maybe a heavy downpour has changed a racecourse’s going) or previously unknown information, such as when football team sheets are revealed an hour or so before kick-off – key players being rested by their manager will usually see that team’s odds lengthen.

Ultimately, the weight of money that comes in for a particular betting market will inform how the odds change over time.

Do Odds On Bets Always Win?

We know that odds-on bets have a greater chance of landing because their implied probability tells us as much.

But the reason that hundreds of millions of people watch sport around the world is that it’s often unpredictable and surprise results happen – those greatly undermine the theory of implied probability, although over a long-term period more odds-on bets win than lose.

Before you go off and bet on odds-on shots blindly, it’s worth remembering that making money with shorter odds selections can be difficult. If you backed ten 1/10 shots, you’d need all of them to win (at level stakes) to realise a profit. Given that 1/10 bets win on 91% of occasions, according to the law of probability, you can see that you’re already chasing your tail on that front.

And you’d be surprised how often odds-on chances don’t oblige in any sport of your choosing…

Here’s a look at the odds-on teams in a Premier League game week:

By betting on these eight odds-on teams, you would have enjoyed a healthy win ratio of 62.5% – excellent by any measure.

But look at the monetary outcome of betting on those games with £10 level stakes: you’d have actually lost money despite winning nearly two-thirds of your bets.

And that explains clearly the myth that odds-on bets always win… or that they are profitable in the long run, anyway.

The Worst Odds On Losses of All Time

There have been some staggering odds-on losses in sporting history.

In 2018, a horse named Tree of Liberty left punters weeping like a willow when he lost a race at Ludlow priced at 1/20 – an implied win probability of some 95.2%.

Another that immediately springs to mind was Mike Tyson’s defeat to Buster Douglas in 1990. Tyson, the so-called ‘Baddest Man on the Planet’, had won his prior 37 fights – 33 via knockout. Douglas was a cherry-picked opponent designed to allow Iron Mike to showcase his ferocious skills in front of a packed Tokyo crowd.

But Buster had other ideas, knocking out the champion in the tenth round as a 42/1 underdog. Tyson, meanwhile, was priced at 1/27… an implied probability of 96.4%. Ouch!

That underdog story can be bettered, believe it or not. In 2007’s college football season in America, the all-conquering USC Trojans were taking on Stanford and were expected to win so comfortably that they were given a -39 point spread.

Well, you can probably guess what happened next. Stanford somehow defied the odds, literally, to win 24-23. USC’s odds? -14,900 using the American moneyline system. That meant their implied probability of winning was an eye-watering 99.3%.