Kalshi Parlay Math: Why 3 Correlated Legs Are Worth 22.1%, Not 17.4% | Combo Edge

September 21, 2026 · Short · Tool Demos

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What’s in this video

This Tool Demos segment walks through a three-leg combo on one NFL game built from Kalshi contracts: a Ravens moneyline position, Ravens team total over 23.5, and Lamar Jackson 250+ passing yards. It shows why multiplying the three legs as independent gives a naive 17.4% figure, while the Combo Edge Builder's joint scoreline model puts the true combined probability at 22.1%. The segment then translates that probability into a fair multiplier band and compares it to the platform's quoted price to reach a verdict.

Key points

The three legs are correlated: a Ravens win tends to push the team total up, which tends to mean more Lamar Jackson passing yards.
Naive multiplication of the three leg prices gives 17.4%, understating the true joint probability.
The Combo Edge Builder instead sums every scoreline where all three legs hit, producing a 22.1% joint win probability, a +27% correlation bonus over the naive math.
22.1% implies a fair multiplier of 4.52x, with a fair band spanning 3.93x to 5.32x.
The platform's quoted multiplier of 5.6x sits above the fair band, with EV of +24% and a quarter-Kelly size of 1.3% of bankroll.
The combo was given a SMASH verdict, the top tier of the tool's 7-tier verdict ladder.

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