Sportsbook

Bet builder: an accumulator within a single match

Bet builder (same game parlay) is a single bet on several outcomes in one match, for example a team to win, over 2.5 goals and the striker to score. The outcomes are correlated, so the odds come from a model rather than simple multiplication, and the margin is higher than on singles.

Yevhen SychovOctober 2026

How it works

The player builds a bet from the markets of a single match: result, total goals, goalscorers, cards, corners. It wins only if every part comes in, as in an accumulator. But outcomes in the same match are correlated: when the favourite wins, there are usually more goals and its striker scores more often.

Formula and example

Fair odds = 1 / probability that all the outcomes land togetherFor example, a home win with a probability of 48% and over 2.5 goals with a probability of 50%. If they were independent, together they would be 24%, with fair odds of 4.17. But the home side wins more often in high-scoring matches: the model gives 29% and fair odds of 3.45, and the player is offered 3.10.

Simply multiplying the odds would give the player a price above the fair one: 4.17 against 3.45. That is why a bet builder is priced with a correlation model.

Margin and players

The margin on a bet builder is higher than on singles: the player cannot compare the price of the combination with the market. In the example, 3.10 against a fair 3.45 is about 11%, while on a standard 1.90 / 1.90 market it is about 5%.

Bet builders are popular with recreational players: the bet tells the story of the match, and a small stake gives a big potential win. Professional players hunt for errors in the model, so limits here are usually lower than on singles. In-play, a bet builder is not available on every market: the correlations have to be recalculated as the match goes on.

How to use it in promos

  • A bet builder free bet on the match of the player's favourite team. It costs less than its face value: a €5 free bet at 3.10 with a 29% probability costs about €3 on average.
  • Ready-made bet builders for the round's main matches in a mailing: the player does not have to build the bet themselves.
  • Minimum odds and a stake limit in the terms, otherwise the promo gets placed on a combination of near-certain outcomes.

Common mistakes

  • Correlated outcomes in a regular accumulator. If the result and the total goals of one match can be combined in an accumulator, the prices multiply and come out above the fair one. Such combinations are blocked.
  • Costing the free bet at face value. For the budget, use the expected payout: the probability of all the outcomes landing together multiplied by the winnings.
  • No rule for a void leg. A player did not take the field, and the market on them is void. The rules state in advance whether the bet is resettled without that leg or voided entirely.
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