Odds


Also known as the price. The chance a bookmaker offers for a selection to win. It can be displayed in several ways:
Traditional or fractional betting is a ratio expressed as a fraction of total profit. A £1 winning bet at 4/1 would win £4, but return £5 (counting your original £1 stake). Profit is calculated by multiplying the fraction by the stake; so a £5 win at 7/4 is (7/4x5=8.75).
Decimal betting is a ratio expressed as decimal number, indicating the total return. A winning £1 bet at 5.0 would also return £5 (£4 winnings plus £1 stake). The return is calculated by multiplying the odds by the stake. 5.0 decimal is equal to 4/1 in fractional form.
U.S. betting is a ratio based around the total of 100. For positive figures, the odds are what you would win on a £100 bet, while a minus sign before the number indicates how much needs to be staked to win £100. For example, 400 is equivalent to 4/1 or 5.0, while -125 is equivalent to 4/5 or 1.8.

Odds Against


When the amount you receive for a winning bet, not including your returned stake, is more than the amount you staked. The selection is deemed to have a less than 50% chance of success.

Odds Compiler


A person working for a bookmaker who sets the odds. The odds compiler is usually an expert on one or two sports and concentrates entirely on these sports.

Odds On


When the amount you receive for a winning bet, not including your returned stake, is less than the amount you stake. The selection is deemed to have a more than 50% chance of success. For example you stake £1 at 8/13 (13/8 on) and receive £1.62, made up of your £1 stake and 62p winnings.

Off-Course


Away from the racecourse or event. This covers bookmakers operating retail outlets, telephone and internet services.

Off-Shore


Bookmakers who are based outside the UK. There are three types of off-shore bookmakers: (i) those that are the off-shore site run by an existing British bookmaker; (ii) those that are existing off-course bookmakers in another country, often Ireland; (iii) internet and/or telephone bookmakers set up specifically to conduct off-shore business.

Off The Board


Term used to signify that the bookmaker is not accepting bets on a particular event.

On-Course


At the racecourse or event.

Outsider


A participant in an event considered unlikely to win, which will be reflected in large odds.

Over-round and Over-broke


Adding up the probabilities as shown by the odds of all the participants in an event for a particular bookmaker gives a percentage. While mathematically the total probabilities of all participants in an event must be 100% (one participant - and only one - can win), bookmakers total percentages add up to over 100%, with the excess their profit margin. A book over 100% is called over-round, and a book under 100% is called over-broke. Over-broke means that a punter could back all the participants and know that the total of their lost stakes will be less than their winnings, if they have staked accordingly (an inviting, if rare, thing).

Over/Under


A type of bet in which the punter bets on whether the total combined points, runs, goals, etc of both teams in the game will be more or less than a set figure, chosen by the bookmaker.

Overs


This is where you bet that the total will finish above the spread.