Exchange betting has its own vocabulary. This glossary defines the key words in plain language and shows each one in a small sum, so the terms stay with you after the page is closed.
Most entries refer to the same invented bet: a backer stakes 10 units on an outcome at decimal odds of 3.0 and a layer takes the other side. Following it from entry to entry shows how each term fits into one transaction. The numbers are illustrations, not live prices.
Grouping the vocabulary makes it easier to learn. Each card names a group and says what it covers.
Back and lay. Two ways to take a position on the same outcome.
Stake, profit and liability, which describe how much is wagered and what is at risk.
Decimal odds, matched and unmatched offers, which describe how a bet is agreed.
Net winnings and commission, which describe what the operator charges and when.
The first words to learn, with the running example attached.
To bet that an outcome will happen. Backing 10 units at 3.0 returns 30 in total if you are right, which is a profit of 20.
To bet that an outcome will not happen. The layer of that 10 unit bet wins 10 if the outcome fails to occur.
The amount the backer puts at risk. In a lay bet the stake that is offered is the backer's, while the layer risks liability.
The most a layer can lose. In the running example it is 10 times 2, which is 20, because the odds minus one is 2.
A price written as one number. At 3.0, a stake of 10 returns 30 in total, including the stake.
A single question with one answer once the event is over, for example the winner of a match.
One possible answer inside a market, such as a team or a player.
These words matter once you understand back, lay and liability.
A back or lay offer that another customer has taken at the stated price, so it is now binding.
An offer still waiting for someone to take it. You can usually cancel it until it is matched.
The total profit in one market after the results of all your bets in that market are combined.
The operator's charge on net winnings in a market. Betfair's help page says losing bets are not charged.
Taking the opposite position after a price move to lock a result that no longer depends on the outcome.
Betting while the event is live, when prices change as things happen.
The step after an event ends, when winners are paid and commission is worked out on net winnings.
Try these by hand before looking at a live market. All figures are invented.
Stake 10 at 3.0. Total return 30, profit 20. If commission applies to a net win in the market, it comes out of that profit.
Offer a 10 unit bet at 3.0 and the outcome fails. You keep 10 of the backer's money. Commission applies if your net market result is a win.
The outcome happens. You owe 20, your liability, and no commission is charged on a losing result.
Definitions on a real market can differ from the general ones here.
Each market carries its own rules. They override anything in a general glossary.
Betfair names Live Messenger, a Facebook direct message and the BetfairCS Twitter account.
Non-UK customers can use eCOGRA after a deadlock email and refer gaming complaints to the Malta Gaming Authority.
A few extra clarifications that readers often need.
No. For a backer they can coincide, but for a layer liability is the backer's stake times the odds minus one, which can be much larger.
Decimal odds make arithmetic simple: multiply the stake by the odds to get the total return including the stake.
No. It is calculated on net winnings per market and not on losing bets.
A market is the question and a selection is one possible answer. Back and lay bets are placed on selections.
It means another customer has taken your offer at your price. Until then it is unmatched.
The core terms are identical. Sports add their own words, such as innings in cricket or the draw in football.
Back and lay, explained