Combine selections into one parlay ticket: combined odds, true probability, payout and profit.
A parlay multiplies the decimal odds of every selection, so three 2.00 legs pay 8.00. The probability multiplies too: three 50% chances make a 12.5% chance. The payout grows fast and so does the chance of losing everything.
The calculator shows combined odds, true probability, payout and profit, plus the margin you are paying — because the book’s edge compounds with every leg you add.
If each leg carries a 4% margin, a four-leg parlay carries roughly 15%. That is why parlays are the most profitable product on any sportsbook and the worst-value bet available to you.
Correlated legs are the exception worth understanding: when outcomes are genuinely linked, the true probability is higher than the multiplication suggests — which is precisely why books restrict those combinations.
Combining selections multiplies the odds — and multiplies the margin with them. Four legs each carrying a 4% margin produce a ticket with roughly 15% baked in, which is why parlays are the most heavily promoted product in any sportsbook.
The appeal is real and it is about shape, not value: a small stake with a large ceiling. Priced honestly, that is the same trade as a high-volatility slot, and it should be sized the same way.
One exception is worth knowing. If you genuinely hold an edge on each individual leg, combining them compounds that edge as well as the margin — but the edge has to be real on every selection, and adding a leg you are unsure about destroys the ticket.
The opposite. Each leg adds its own margin, so expected value falls as the ticket grows even though the headline payout rises.
Most books drop the pushed leg and recalculate the remaining ones, which lowers the payout without voiding the ticket.