A back bet is a bet that an outcome will happen: a runner to win, a team to win or cover the line, a player to score. That is the whole meaning of backing, and every bet you place with a bookmaker is a back bet. On a betting exchange, backing is one of two sides, and the punter who takes the other side of your bet is laying it.
How a back bet pays
Decimal odds include the stake, so a winning back bet returns stake x odds. The bet calculator works out the return and profit for a single bet. With illustrative prices, backing $20 at $4.00:
| At a bookmaker, $4.00 | On an exchange, $4.00, illustrative 7% commission | |
|---|---|---|
| Stake | $20 | $20 |
| Returned if it wins | $80 | $75.80 |
| Profit if it wins | $60 | $55.80 |
| Lost if it loses | $20 | $20 |
| Pays like a bookmaker price of | $4.00 | $3.79 |
At the bookmaker, 20 x 4.00 = $80 comes back, of which 20 x (4.00 - 1) = $60 is profit. On the exchange the same win is charged commission on net winnings in the market, at whatever rate the exchange sets: at 7%, 60 x 0.07 = $4.20 comes off, leaving $55.80. That makes the exchange's $4.00 worth 1 + 3.00 x (1 - 0.07) = $3.79 against a bookmaker price, so a bookmaker offering $3.80 would pay slightly more. A losing back bet pays no commission.
Back odds and lay odds on the exchange
An exchange shows two prices for each selection. Back odds are the prices you can back at now, offered by layers; lay odds are the prices you can lay at now, offered by backers. A team might show $2.88 to back and $2.90 to lay.
The best back price always sits below the best lay price, because offers that meet are matched and leave the ladder. In a busy market the gap is usually one tick, and in a thin one it can be many.
If a backer asking $2.90 met a layer offering $2.90, their bets would be matched and both offers would disappear. What stays on screen is the layers' best offer, $2.88, and the backers' lowest ask, $2.90: two prices the sides have not agreed on yet. That gap is the back lay spread, and the market's fair price is usually taken to sit inside it.
Backing compared with laying
| Backing | Laying | |
|---|---|---|
| You are betting that | The outcome happens | The outcome does not happen |
| The most you can lose | The stake | The liability: lay stake x (lay odds - 1) |
| What you win | Stake x (odds - 1) | The lay stake, which is the backer's stake |
| Where | A bookmaker or an exchange | An exchange: a bookmaker is the layer on every bet it takes |
Laying the same $20 at $4.00 puts 20 x 3.00 = $60 at risk to win $20, the mirror image of the back bet. Liability explains that number, and how to lay a bet walks through placing one.
Backing at a bookmaker or on an exchange
Both are back bets, but they differ in ways that change the result, and how betting exchanges work covers the exchange side in full:
- Price. A bookmaker builds its margin into every price, while an exchange price carries no margin and exchange commission comes off winnings instead.
- Matching. A bookmaker accepts the bet, accepts only part of it, offers a different price or refuses it. An exchange back bet waits until a layer takes it, so part of it can go unmatched.
- Promotions. Bookmakers issue bonus bets and other offers under their own terms; exchanges do not hand them out the same way.
- Accounts. A bookmaker can limit or close an account, and an exchange has its own terms too, so read both.
How the two sides fit together, from liability to commission, is in the lay betting guide.
Comparing back prices across bookmakers
On the Terminal each bookmaker has its own column of back prices, runner by runner or selection by selection, with the best available price on each picked out and Betfair back and lay beside them. A free account opens a limited view of the Terminal with live odds, without the Betfair prices. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
Risk: Betting involves risk. A back bet at a good price can still lose, the margin and any commission reduce what a winner pays, and there is no guarantee of profit. See responsible gambling for limits and support.