How to Calculate +EV on Same-Game Parlay Boosts

Same-game parlays are usually a terrible bet. The correlation between legs means the true odds are different from what the parlay math suggests, and books build in extra margin.

But when sportsbooks offer profit boosts on SGPs — 25%, 50%, even 100% boosts — the math can flip in your favor.

How SGP Boosts Work

A sportsbook might offer: "Get a 50% profit boost on any 3+ leg same-game parlay for tonight's NBA game."

If your parlay would normally pay +400, the boost makes it +600. The question is: does +600 represent positive expected value given the true probability of the parlay hitting?

How to Calculate SGP EV

The StackDubs SGP Calculator lets you:

1. Add legs: Enter each leg of your parlay with the odds
2. Set the boost: Input the profit boost percentage
3. Calculate fair value: We devig each leg to estimate the true probability
4. See the EV: Compare the boosted payout to the fair parlay odds

If the boosted odds exceed the fair odds, the SGP is +EV.

The Correlation Problem

The tricky part with SGPs is correlation. If you parlay "Player A Over 25.5 points" with "Team A to win," those outcomes are positively correlated - if the player scores a lot, the team is more likely to win.

Sportsbooks account for this by adjusting SGP odds downward. Our calculator uses the individual leg odds to estimate fair value, which gives you a baseline. The actual edge may be slightly higher or lower depending on correlation.

When SGP Boosts Are +EV

Generally, boosts are +EV when:

The boost percentage is large (50%+ on a 3-leg parlay often crosses the +EV threshold)
The legs have low correlation (mixing props from different players, or combining a total with a player prop)
The underlying odds are sharp (use the best available line for each leg, not the boosted book's base odds)

A Quick Example

Three-leg SGP with fair odds of +350. The book offers a 50% profit boost, making the payout +525.

Fair implied probability: 1/4.5 = 22.2%
Boosted decimal odds: 6.25

EV% = (6.25 × 0.222 - 1) × 100 = +38.8% EV

That's a strong +EV play.

Getting Started

Open the SGP Calculator, add your legs, input the boost percentage, and we'll tell you if it's worth taking. Not every boost is +EV, but when they are, they're some of the highest-edge bets available.

Don't let sportsbooks use boosts as marketing bait. Use math to find the ones that actually pay.