Any newcomer to the world of betting is bound to hear or see words and abbreviations they have never heard of before. As some of these relate to the odds themselves, it helps to be familiar with the lingo before you part with your cash. This is why we are going to cover five key odds-related terms: evens, odds-on, SP, odds shortening and odds drifting. Once you have finished reading, we are confident you will have a full understanding of each, allowing you to use them just as a veteran gambler would.

## The Basics of Betting Odds

Before we delve into some of the more common terms relating to betting odds, let’s first briefly explain what betting odds are. Though things can get rather technical and mathematical when odds are related to the probability of particular outcomes, we’ll attempt to keep things rather simple here.

As such, we would suggest that the betting odds given for a particular outcome represent the amount you would win if you placed a bet on that outcome and it happened. For example, in a football match, the odds on the home win would tell you what you would win if you placed a bet on the home team to win and indeed they did win.

### Fractional & Decimal

Although odds can be written in various formats, the most common in the UK are fractional (such as 10/1 or 6/4) and decimal (such as 6.00 or 1.50). To keep things as straightforward as possible here, we’ll stick to fractional odds, which have been the more traditional odds format over the years in the UK.

With fractional odds, the fraction represents the chance of a particular event occurring, although in reality, it is not quite as simple as that because of the great number of variables with sporting events and also the fact that the bookmaker will always build in a margin. When looking at fractional odds, the numerator (the number on the left or top of the fraction) represents the winnings you would get back if you bet the amount given by the denominator (the number on the right or bottom of the fraction). So, for instance, if you bet £1.00 on a horse to win a race at odds of 10/1, if the horse wins, you’ll receive winnings of £10, plus your £1 stake, so £11 in total.

### How Odds Work

For an example, let us assume the odds perfectly reflect the probability of an outcome and the outcome in this case is rolling a six on a six-sided dice. We will also assume the dice is fair, i.e. that is, it is not weighted or “loaded” in any way. In such a scenario, the probability of you rolling a six would be 1/6, but – perhaps confusingly – the odds for you rolling a six would be 5/1, which would be spoken as “five to one”.

The reason the odds are 5/1 and not 6/1 is that the odds of 5/1 represents a probability of 1/6 (a sixth) or 16.66667% (16.6 recurring per cent). Odds of 6/1, meanwhile, would represent a probability of a seventh, or just over 14%. If you take an even simpler example of a coin toss, with head and tales each having a 50% chance of landing, the odds (without the complication of the bookie’s margin) would be 1/1, which represents a probability of 50% of a half. This is also known as “evens”.

## What Is Evens in Betting?

Let’s explain a little more about the term “evens”’, something you will see across almost all sports. The term itself is short for “even money” and it relates to the price of a particular bet whether it be a football team, a horse, a greyhound or tennis player. With a bet that is priced at odds of evens, you stand to win whatever the value of your stake was, making it an “even” return so to speak. If you were to bet £5, for example, at evens you would receive £5 in net win (plus your £5 stake back) if it turns out to be successful.

When such a price is offered, some bookmakers will write “evens” or sometimes shorten it further to “EVS”. Others, however, prefer to display it in a numerical form, written as 1/1, as mentioned above. When in its fractional form, it is easy to see that whatever you put in (the second number or the denominator) is the same as whatever you stand to get out (the first number or numerator).

As explained above, fractional odds work in this way across the board so for a 2/1 bet you are getting £2 back for every £1 bet. If the fraction involves larger numbers, e.g., 10/3, you are not obligated to bet £3 but it simply means you are paid out at the equivalent rate of £10 for every £3 you bet or stake.

Although for the punter, an evens bet implies there is a 50% chance of success, remember that bookmakers enjoy a (usually relatively small) margin on all bets offered. If there are just two options for a particular betting market, you will never, therefore, see both outcomes offered at evens. If one player or team is at evens, then the other is most likely trading at or around 8/11. Because bookies need the odds to be slightly in their favour, in situations they think two outcomes are equally likely, they will advertise odds just under evens for both, such as 5/6 or 10/11. When the number on the left of the fraction in fractional odds is smaller than that on the right, the bet is said to be “odds on”.

## What Are Odds-On Bets?

Although not limited to just horse racing, it is within this sport that you are most likely to hear the term odds-on. It is used to indicate any horse that is trading at odds shorter than evens. By shorter we mean odds that will return less of a net win than the initial stake because the outcome is deemed more likely to happen. If there were an odds-on 1/4 favourite, for instance, the implied chance of success is 20% so we would only get £1 net win for every £4 wagered (or £0.25 net win for every £1 wagered).

Prices, such as 1/3, 1/10, 5/6 and 4/9, are all examples of odds-on options. They are always very easy to spot because the first number will also be smaller than the second number when in fractional form. Across other sports, the term is less commonly used because it is less insightful. Many football matches, for example, will have an odds-on team purely because there are only three outcomes to choose from (home win, away win, draw) so often you will just refer to simply “the favourite” instead though you could still refer to the “odds-on favourite” in this case. Having an odds-on horse by contrast is not something a lot of races have so when you do see one, the degree of market confidence is more of a talking point.

You will find odds-on used across other sports though when looking at things, such as league or tournament winners. Saying that Alexander Zverev is now odds-on for Wimbledon or that Chelsea are the odds-on pick for the league title are both two natural-sounding examples. In both cases, it is because you would not ordinarily expect a team or player to have such a small price given the number of other options available.

### What Are Odds-Against Bets?

Although less commonly used, “odds against” is simply the opposite of “odds on”. Therefore, any bet trading at greater than an even-money price, and therefore given less than a 50% implied probability, would be classed as odds-against. Examples of odds-against prices include 11/10, 2/1, 10/1, 500/1, 12/5.

## What Is the SP in Betting?

SP is something you will only ever see when betting on horse or dog racing. It stands for “starting price” so quite literally the price the dog/horse was available at when the race was about to start. Although this sounds simple, the starting price is not just a matter of what price the bookmaker you were using was offering. Instead, an independent body takes odds from a variety of online and on-course bookies to produce an average price. This is the figure all bookies must use as the starting price, no matter if they offered higher or lower odds to their own customers.

This is important because a lot of bookmakers, especially on UK and Irish horse racing bets, offer some form of “best price guaranteed” policy. Thanks to such policies, punters that place a “fixed-odd” horse bet, for example, betting on a horse at odds of 7/1, will – if their horse wins – be paid out at the SP, if the SP ends up being greater that the odds they took. If the SP ends up being lower than the fixed-odds that were taken, however, the punter is simply paid out at the fixed-odds price so it is something of a win-win for them. As long as their horse wins, of course!

It is also possible to simply bet on the SP to begin with if the market is yet to open. When this happens all horses/dogs will simply be listed as SP so you just need to choose your runner and your stake. You will not know what you stand to win until later but you can rest assured that you will be getting a fair price (or at least an average price). Starting price calculations are always based on averages and are designed to be an accurate reflection of the market as a whole.

## What Does It Mean When Odds Are Shortening/Drifting?

One thing you will quickly realise when betting is that odds change, especially if the match/event/race in question is close to starting. Odds can change based on new information but most commonly they change because of punters placing their money on the various possible outcomes. If several customers place significant sums of money on a particular horse, for instance, bookies respond by shortening the price. If a horse was trading at 2/1 but is now available at 6/4, the price has “shortened” or “come in”, so future bets will stand to win less money if that horse wins.

Prices can go the other way though and they often do when they have little market support. If a horse that was trading at 10/1 is now up to odds of 12/1, the price has “drifted” or “gone out”. It may be the case that more drifting occurs with the price going out to 14/1 and then 16/1. Ultimately, there are no rules about how much the odds can drift or shorten so timing your bets right becomes something of a skill. Suffice to say, the odds don’t matter all that much if you don’t pick a winner!