The PromoGrind SGP Estimator calculates the fair odds of a same game parlay and compares them to the sportsbook's posted price — revealing the true vig and whether an SGP boost puts you in positive EV territory.
Use the SGP Calculator →A same game parlay combines correlated legs from the same event (e.g., a QB to throw 300+ yards and his team to win). Standard parlay math multiplies independent probabilities, but SGPs involve correlation adjustments — the book's proprietary correlation model is unknown. The estimator uses a conservative independence assumption to give you a baseline fair-odds floor.
SGP profit boosts (e.g., "25% profit boost on any 3-leg SGP") can push the boosted odds above fair value. Enter the fair odds, your stake, and the boost percentage — the calculator shows whether the boosted payout exceeds the expected cost of the bet. Most SGP boosts have max win caps that also affect EV; those are factored in.
Regular parlays use published straight-bet odds with a fixed parlay payout table. SGPs use the book's internal correlation model — which typically results in shorter odds than a regular parlay would give you on the same legs. That's why comparing the SGP price to the regular parlay price is a useful vig check.