Bet Builder (in the US, Same Game Parlay, SGP; with some bookmakers, the “bet constructor”) lets you combine several outcomes from a single match into one bet with a single set of odds. For example: a team to win + over on the total + a specific player to score — all on one ticket. If every selected outcome lands, the bet wins; if even one misses, the whole bet loses.
The format has become one of the biggest trends in betting, yet a lot about it is misunderstood: why a bet builder’s odds don’t equal a simple multiplication of the individual odds, where the higher margin comes from and how this affects a bettor over the long run. We’ll unpack the mechanics and the maths without predicting outcomes and without advice on what to bet on — only how the tool works. Odds are always an estimate of probability plus the bookmaker’s margin, not a promise of a payout.
Key takeaways
- Bet Builder / SGP is a combination of outcomes from ONE match into a single bet.
- The difference from an accumulator: in an accumulator the outcomes come from different matches and are independent; in a bet builder they come from one match and are correlated.
- Because of that correlation, the odds are calculated not by multiplication but from a joint-probability model.
- The margin in a bet builder is higher than on single bets: a benchmark of 15–25%+ versus 4–5%.
- Cash out on a bet builder is usually guaranteed pre-match; in-play it may be limited.
- 18+. This content explains the mechanics and the rules; it gives no betting advice and predicts no outcomes. Betting carries the risk of losing money.
What Bet Builder and Same Game Parlay are
Bet Builder is a tool that lets you combine several markets within a single event into one bet. bet365’s help pages put it plainly: a Same Game Parlay lets you create a custom bet by combining several selections from one match. It’s available both pre-match and in-play on supported sports.
The terminology differs by bookmaker, but the idea is the same: bet365 uses “Bet Builder” (in the US, “Same Game Parlay”), BetMGM has “Parlay Builder”, and DraftKings uses “Same Game Parlay”. Combining several builders from different matches into a single accumulator is called Bet Builder+, SGP+ or SGPx.
How a bet builder differs from a regular accumulator
On the surface a bet builder looks like an accumulator, but the fundamental difference lies in the dependence between the outcomes — and that is exactly what determines the odds.
| Parameter | Regular accumulator | Bet Builder / SGP |
|---|---|---|
| Events | Different matches | One match |
| Dependence between outcomes | Independent | Correlated |
| How the odds are calculated | ≈ multiplication of the odds | Model adjusted for correlation |
| Typical margin | ~10% (accumulator) | 15–25%+ |
| Term | Accumulator / parlay | Bet Builder, SGP, Parlay Builder |
Why the odds aren’t a simple multiplication (correlation)
In a regular accumulator built from different matches the outcomes are independent, and the odds are close to the product of the individual legs’ odds. Within a single match the outcomes are linked: if a team is winning comfortably, so grows the chance that its striker scores and that the total goes over. Such outcomes are correlated, so a naive multiplication of probabilities gives the wrong answer, and bookmakers price a bet builder using a joint-probability model.
A telling calculation from Wizard of Odds: three outcomes at odds of −110 (a 52.4% probability each). The naively multiplied probability = 0.524³ ≈ 14.4%, which corresponds to a “fair” price of about +594. But once positive correlation is taken into account, the real joint probability turns out higher — around 21.2% (roughly a third above the naive figure). Because of this the fair odds are shorter, and the book offers shorter still, building in its margin.
The takeaway for the reader: with positive correlation a bet builder’s odds will be shorter than the product of the legs (it can feel as though you’re being “underpaid”), and with negative correlation they’ll be longer. This isn’t a bookmaker error but a consequence of the outcomes being linked.
| Calculation step (3 outcomes at −110) | Value |
|---|---|
| Probability of each outcome | 52.4% |
| Naive multiplication (0.524³) | ≈14.4% → odds ~+594 |
| Real joint probability (correlation) | ≈21.2% |
| Fair odds accounting for correlation | ≈+372 |
| What the book offers (example) | +350 → edge in the bookmaker’s favour |
The bookmaker’s margin: why a bet builder costs the bettor more
The main thing to grasp about a bet builder: its margin (hold) is noticeably higher than on single bets. On a single at −110 the book’s edge is around 4–5%. For a bet builder / SGP the estimates converge on a range of 15–25%+ (Wizard of Odds), while Pikkit’s measurements give 10–20% and “15–20% with five or more legs”.
The spread between bookmakers is wide. According to Pikkit’s measurements, the best tier for SGPs is bet365 and ESPN (a margin closer to a regular accumulator), the middle tier is Caesars, DraftKings and Kambi, and the most expensive are FanDuel (22–23%) and BetMGM (24%). The same set of outcomes might be priced at, say, +650 at one bookmaker and +850 at another — a difference of about 30% in payout for an identical bet.
Hence the practical point: the more legs in a bet builder, the harder the accumulated margin works against the bettor over the long run. That doesn’t make the format “bad” — but you pay noticeably more for the convenience of putting everything on one ticket than you would for separate bets.
| Bet type | Typical margin (hold) |
|---|---|
| Single bet (−110) | 4–5% |
| Regular accumulator | ~10% |
| Bet Builder / SGP (general benchmark) | 15–25%+ |
| SGP — best tier (bet365, ESPN) | closer to an accumulator |
| SGP — expensive tier (FanDuel, BetMGM) | 22–24% |
Limits: how many outcomes, and what you can’t combine
A bet builder has technical limits. At bet365, for instance, you can add up to 12 selections to a single Same Game Parlay, no more than 6 players from one team and a minimum of 2 selections from the match; there’s also a cap on the maximum odds (per secondary data, up to +100000 — better to confirm in the rules).
The bookmaker blocks or noticeably trims some combinations as too dependent. A classic is a team to win plus that same team on a comfortable handicap: if the team wins, the handicap lands almost automatically, so such pairings are often unavailable. “Softer” combinations (win + team total) are usually allowed. And remember the recalculation rule: if one of the outcomes is deemed void/push, it affects the whole bet — some books recalculate it on the remaining legs, others refund it in full.
Cash Out on a bet builder
Many books let you close a bet builder early via Cash Out — locking in part of the amount without waiting for the match to end. There’s partial cash out (take some, leave the rest in play) and auto cash out (set a target value at which the bet closes itself). The cash-out value updates in real time based on the current odds, the score and the time.
A bet365 nuance: for a Bet Builder, cash out is generally guaranteed pre-match, while in-play it may be limited or temporarily unavailable due to market swings. And one more thing: the cash-out price also has the bookmaker’s margin built in — it’s a convenient way to manage a bet, but not a “fair” market price.
Bet Builder+ / SGP+ and how to read the odds without illusions
Bet Builder+ (SGP+, SGPx) combines several builders from different matches into one accumulator with a higher overall price. In effect, cross-match multiplication is added on top of the within-match correlation, and the total margin stacks — meaning the format is even more expensive for the bettor in expectation.
The mechanics in a nutshell: a bet builder is a convenient but margin-heavy tool. Its odds reflect an estimate of linked probabilities plus the book’s elevated commission, not a promise of a payout. Understanding correlation helps you not be surprised when “three obvious outcomes” produce modest odds, and to judge the cost of the convenience soberly. There are no “can’t-lose schemes” here.
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This content is informational, explains the mechanics and rules of betting and is not advice to place bets or a prediction of match outcomes. Sports betting is 18+ and carries the risk of losing money; the odds reflect probability and the bookmaker’s margin, not a guarantee of winning. There are no “can’t-lose” strategies. Play responsibly.
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Frequently asked questions
How does a bet builder differ from an accumulator?
An accumulator combines outcomes from different matches (which are independent), while a bet builder combines outcomes from one match (which are correlated). Because of that correlation, a bet builder’s odds aren’t calculated by multiplication.
Why are a bet builder’s odds lower than the product of the legs?
Because outcomes from one match are linked. With positive correlation the real probability of the combination is higher than the naive one, so the fair odds are shorter — plus the book builds in its margin.
What’s the margin on a bet builder?
A benchmark of 15–25%+ versus 4–5% on a single bet. The exact figure depends on the bookmaker and the number of outcomes; at some books an SGP is cheaper, at others noticeably more expensive.
Can you cash out a bet builder?
Usually yes, especially pre-match. In-play, cash out may be limited. Partial and auto cash out are available; the cash-out price also has margin built in.
How many outcomes can you add to a bet builder?
It depends on the bookmaker: at bet365, for example, up to 12 selections and a minimum of 2 from one match. Strongly correlated combinations may be blocked.
Sources
- bet365 Help Center — Same Game Parlay / Bet Builder — help.bet365.com
- Wizard of Odds — Same-Game Parlays: The Mathematics of Correlation — wizardofodds.com
- Pikkit — Same-Game Parlay (SGP) Explained 2026 — pikkit.com
- Pikkit — Best & Worst Sportsbooks for SGPs (margin measurements) — pikkit.com
- FOX Sports — What is a Same Game Parlay? — www.foxsports.com
- OddsJam — Why Can't I Parlay Certain Bets (Correlated Parlays) — oddsjam.com
- Establish The Run — The Math Behind Parlay Betting — establishtherun.com