Max win odds calculator

A max win listed as "1 in 20 million" sounds abstract. This turns it into something you can picture: the chance of hitting it in the number of rounds you'll actually play, and how many rounds it takes on average. The odds come from each game's published outcome table.

ModeCost per roundMax winOdds per roundRounds playedChance in those roundsRounds for a 50% chanceExpected cost of those rounds
The chance of at least one max win in N rounds is 1 − (1 − p)N, where p is the odds of a single round. "Rounds for a 50% chance" is how long it takes for that to reach one in two. The expected cost of playing that long is rounds × cost × (1 − RTP), and it is usually far larger than the prize is likely to pay back. A budget overrides the rounds: rounds = budget ÷ (bet × mode cost), as if every round were paid from the budget.

Why max wins are rarer than they look

Every round is independent. A game doesn't become "due" after a long time without a big win, and a hit doesn't make the next one less likely. So the odds per round never change; only the number of rounds you play does.

Two things surprise most players. First, even after playing exactly as many rounds as the odds (say 1 in 1,000,000 and a million rounds), the chance of at least one hit is only about 63%, not 100%. Second, reaching a 50% chance takes about 0.69 times the odds, which on a high-volatility slot is often tens of millions of rounds. See what "1 in N" really means and the slots where the max win is most likely.

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