Parlay Betting Explained — How Parlays Work in Ontario

I'm Andre, "The Six," and I cover the Raptors and the basketball markets for Betting Wingmen Ontario. Parlays — and especially same-game parlays — are the bet type I get asked about more than any other, partly because the apps push them so hard and partly because the math behind them is genuinely confusing the first time you see it. I've built thousands of them across every Ontario book testing how the prices move, so I want to walk you through exactly how a parlay is priced, where the same-game parlay differs, and what the numbers really say about your chances.

This is a no-hype guide. I'll show you a worked example with real American odds and a $20 stake, give you a payout table you can keep, and be straight with you about why long parlays are low-probability bets. By the end you'll know how to build one properly and, just as importantly, when not to.

Picture three separate bets you might place on a Saturday slate: the Raptors to cover the spread, the Maple Leafs on the moneyline, and the over in a Blue Jays game. As three single bets, each settles on its own — win one, lose two, you collect on the one and eat the other two.

A parlay takes those same three picks and welds them into one ticket. Now there is no partial credit. All three have to win for the parlay to pay anything at all. If two land and one misses, the whole bet loses. That all-or-nothing structure is the price you pay for the upside.

The upside is real, though. Because the odds of all three legs multiply rather than add, a parlay returns dramatically more than betting the same three picks separately. Three coin-flip-ish picks at -110 each, bet individually for $20 apiece, would return roughly $38 per winner — about $114 total if all three hit. Parlayed, that same $20 stake returns roughly $139. Same picks, much bigger number, but everything riding on one all-or-nothing outcome.

The mechanics are simpler than they look once you switch to decimal odds. American odds are awkward to multiply, so books (and you, on a calculator) convert each leg to its decimal equivalent, multiply them all together, and apply the result to your stake.

For a -110 line, the decimal odds are 1.909. The formula for converting a negative American line is 1 + (100 / 110), which gives 1.909. A +150 line is 2.50 in decimal (1 + 150/100). To find a parlay's total payout, you multiply the decimal odds of every leg, then multiply by your stake. The number you get back is the total return — stake included — and subtracting your stake leaves the profit.

Here is the worked example, a three-leg parlay of three -110 legs on a $20 stake:

Step 1 — convert each leg. Each -110 leg is 1.909 in decimal.

Step 2 — multiply the legs. 1.909 × 1.909 × 1.909 = 6.957. That is your combined multiplier, and in American odds it works out to roughly +596.

Step 3 — apply the stake. $20 × 6.957 = $139.14 total return.

Step 4 — find the profit. $139.14 − $20 stake = $119.14 profit.

So three modest -110 picks turn a $20 ticket into about $139 back. Compare that to the $114 you'd collect betting the same three picks as $20 singles and you can see the pull of the parlay. The cost of that extra payout is that all three legs must land — and as we'll see in the table below, the more legs you add, the steeper that climb gets.

A standard parlay pulls legs from different games. A same-game parlay — SGP — does what the name says: it stacks multiple bets from one single game onto one ticket. A Raptors moneyline, plus Scottie Barnes over his points line, plus the game total over, all from the same Raptors game.

SGPs blew up in popularity because they're fun to build and they let you tell a story about how one game plays out. But they are priced very differently from a regular parlay, and the reason is a single word: correlation.

Correlation means the outcomes of your legs are related to each other rather than independent. In a regular parlay across three different games, the Raptors result has nothing to do with the Leafs result — the legs are independent, so the book can just multiply the prices. Inside one game, that breaks down. If Scottie Barnes goes for 35 points, the Raptors are more likely to have won that game. So "Barnes over points" and "Raptors moneyline" tend to hit together — they're positively correlated.

If a sportsbook priced those correlated legs by simply multiplying them, it would be handing you a payout that's too generous relative to the true combined probability — you'd be getting paid as if the legs were independent when they're actually linked. To prevent that, books run every SGP through a correlation model that re-prices the ticket. The practical result: a same-game parlay almost always pays less than the same legs would if you could somehow place them across separate games. That isn't the book cheating you; it's the book pricing the real, linked probability of those outcomes.

Building a parlay on any Ontario app follows the same rhythm. Here's the sequence I use, whether it's a cross-game parlay or an SGP.

Step 1 — Pick your legs. Tap each selection you want. For a regular parlay, choose markets from different games; for an SGP, open a single game and look for the "Same Game Parlay" or "Build a Bet" tab. Each tap adds the selection to your bet slip.

Step 2 — Confirm the slip recognizes it as a parlay. Once you've added two or more legs, the bet slip should offer a "Parlay" option alongside the singles. Select it. The combined odds will appear — this is the multiplied price, already correlation-adjusted if it's an SGP.

Step 3 — Check the combined odds and the payout. The slip shows the parlay odds in American format and a "to return" or "potential payout" figure. Read it before you do anything else. If the number looks suspiciously large, that's your cue that you've stacked a lot of legs — and a lot of probability you have to clear.

Step 4 — Enter your stake. Type in what you're risking. The potential return updates instantly. Keep it to an amount you're genuinely fine losing, because most parlays lose.

Step 5 — Compare across books, then place. Before you confirm, it's worth building the same parlay on a second app. The combined price — especially on an SGP — can differ meaningfully between books because their correlation models differ. Take the better price, then place the bet.

This is the table I wish someone had shown me early. It assumes every leg is a -110 line — the standard "juice" price you'll see on most spreads and totals — and a $20 stake throughout. The return is the total amount back (stake included), rounded. It shows you, in one glance, how fast the payout climbs and why that climb should make you cautious rather than greedy.

Look at how the payout explodes — eight -110 legs turn $20 into roughly $3,000. That number is exactly why the apps love to surface long parlays, and exactly why you should be skeptical of them. The payout grows because the probability shrinks. Each leg at -110 implies a little over 50% to win after the juice, and you have to clear every single one. Stack eight of them and the combined chance of cashing is a sliver of a percent. The big number is the bait; the tiny probability is the hook.

Here's the part the marketing never mentions. Every -110 line carries a built-in margin for the book — that's the difference between the fair price and what you're actually offered. On a single bet, that margin is small enough that sharp picks can overcome it. In a parlay, that margin doesn't just sit there; it compounds with every leg you add.

Think of it this way: if each leg costs you a few cents of edge, a single bet costs you a few cents, a three-leg parlay costs you that margin three times over, and an eight-leg parlay multiplies it eight times. The longer the parlay, the more the house edge stacks against you. That's a mathematical fact, not a matter of luck or timing, and it's the single most important thing to understand before you build a big ticket.

None of this means parlays are bad — it means they're a high-variance bet, not a profit engine. A two- or three-leg parlay on picks you genuinely like is a reasonable swing. An eight-leg moonshot for a small stake can be a fun flier as long as you treat it like the lottery ticket it mathematically is. The mistake is believing a long parlay is a smart way to grow a bankroll. It isn't. The number on the screen is large precisely because it almost never happens.

If you're going to bet parlays — and most Ontario bettors do, at least occasionally — a few principles keep you on the right side of the math.

Fewer legs, not more. Two and three-leg parlays give up far less edge than five-plus-leg tickets. If you want to bet a parlay seriously rather than as a flier, keep it short.

Value legs over "obvious" legs. Stacking three heavy favourites at short prices doesn't pay much and still requires all three to land. Look for legs where you think the price is genuinely a bit better than the true probability — that's where a parlay can actually work in your favour rather than just amplifying the juice.

Don't force correlation the book has already priced. On an SGP, the obvious "star scores big AND team wins" combo is exactly what the correlation model has accounted for, so you're rarely getting a bargain there. The value, when it exists, tends to be in less obvious pairings.

On which books price same-game parlays sharpest, two names come up consistently in my testing: FanDuel and DraftKings. Both have mature SGP builders with a deep menu of combinable markets, well-developed correlation pricing, and clean bet slips that show you the combined odds clearly before you commit. That depth is a durable strength — it comes from years of building these products, not from any promotion. Both are licensed through iGaming Ontario and the AGCO.

That said, "sharpest builder" doesn't mean "always best price." Because correlation models differ, the same SGP can come back at noticeably different odds across apps. Build your ticket on two or three books and take the best combined number. You can line up the full slate of licensed Ontario options in our reviews to find the apps whose SGP product fits how you actually bet.

Long parlays are low-probability bets — that's the honest core of this whole guide. The big payouts on the screen exist because cashing them is rare, and no amount of leg-stacking changes that math. Treat a parlay as entertainment with a small, defined stake, not as a way to win back a losing day. Chasing losses with bigger and longer parlays is the fastest way I know to turn a bad night into a worse one.

Set a budget before you build the ticket, and stick to it. Every Ontario book offers responsible-gambling tools — deposit limits, time-outs, and self-exclusion through BetGuard — and they're worth setting up before you need them. You must be 19 or older and physically located in Ontario to bet, and if gambling is starting to feel like more than entertainment, ConnexOntario offers free, confidential support 24/7 at 1-866-531-2600. Recreational betting winnings in Canada are tax-free, but the only winnings worth chasing are the ones you can afford to lose.