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If events are independent, the chance that all of them happen is the product of their probabilities, and the chance that at least one happens is 1 minus the chance that none do. Three markets at 60%, 70% and 50% give 21% for all three and 94% for at least one — a “parlay” of favourites is much less likely than any single leg.
Assumes the events are independent. Related events (same election, same team) move together, so the true “all” chance can be much higher or lower.
Polymarket has no parlay button: to back several outcomes together you buy each one separately. Holding every leg is not the same bet as a sportsbook parlay — each leg pays on its own — but the calculator shows how rarely a string of favourites all come in, which is why parlays pay so much and why books like them.
Check each leg's current price on Polymarket odds today, and remember the taker fee on every purchase.
Multiply their probabilities, if they are independent: 60% × 70% × 50% = 21%.
Multiply the chances that each one fails and subtract from 1: 1 − (0.4 × 0.3 × 0.5) = 94%.
No. If the events are linked — two markets on the same election, for example — the simple product is wrong, because one outcome changes the chance of the other.
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