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Prediction Market Parlay Calculator

Enter each leg's price in cents to see the fair combo price (the product of the legs), the chance all of them hit, and — if you paste the price you were quoted — the markup it adds.

Prediction Market Parlay Calculator

Legs (2)

Each leg's price in cents (1–99) is its implied chance. Up to 10 legs.

The single price you were offered for the whole combo. Leave blank to see just the fair price.

Combos, plain

What a "combo" is

A combo (the prediction-market name for a parlay) links several outcomes into one bet that pays $1 per contract only if every leg resolves in your favor. Miss one leg and the whole thing settles at $0.

Because each contract price in cents is that leg's implied probability, the fair price of the combo is just the legs multiplied together: four legs at 60¢ → 0.60⁴ = 0.1296, about 13¢.

Where the markup comes from

The fair price is what the combo is worth if it's priced at exactly the product of its legs. Any quoted price above that is markup — the margin charged by whoever takes the other side of the trade.

That's the same role the vig plays on a sportsbook. Pasting your quoted price next to the fair price shows the gap in cents and as a percentage, so the markup isn't hidden inside one combined number.

Markup is not the same as fees

This tool compares your quoted combo price to the fair product of the legs. Platform trading fees (for example a per-contract taker fee) are charged separately on top of the price — use the fee calculator for those. Combined, the markup and the fees are the full cost of placing the combo.