Sports Betting Calculators: Odds, Parlay, Hedge and Arbitrage Tools
Our betting calculators for Ontario work out what a bet pays, the chance its odds imply, how much the book keeps, how to stake a parlay, a hedge or an arbitrage, and how much to bet on an edge – five free tools in American or decimal odds.
Each one does a simple sum: odds into a payout, odds into a probability, two prices into the book’s margin, or several prices into a split. To see what each Ontario book actually charges, our Ontario sportsbook margins page ranks 14 books on the same NHL games. This page explains, with real prices, the arithmetic behind each one – so you can check any number a sportsbook shows you.
The examples use the money lines we read on 29 October 2026 on four NHL games that night – Blue Jackets at Hurricanes, Mammoth at Penguins, Jets at Lightning and Senators at Kings – at 15 Ontario sportsbooks.
Our Betting Calculators
The payout and profit on any bet, the odds in American, decimal and fractional, the implied probability – and, with the other side entered, the book’s margin and the fair odds.
What a multi-leg ticket pays, with pushes, and how much of the stake the book keeps once every leg has been charged its margin.
How much to bet on the other side to lock in a profit or get your stake back, for a single bet, the last leg of a parlay or a futures ticket.
Whether the best prices at different books add up to an arb, and how to split the stake across two or three outcomes, with rounding.
How much of your bankroll to stake on a bet with an edge – at full, half or quarter Kelly – and the fair chance from a sharp book’s two prices.
Each calculator works in American and decimal odds – the odds, parlay and Kelly calculators also read fractional – runs in your browser and stores nothing. All of them are for information: the bet slip at your sportsbook is what counts.
Which Calculation Answers Which Question
Each question about a bet comes down to one sum, and one of our five calculators does it:
| Your question | The calculation | Calculator |
|---|---|---|
| How much does this bet pay? | Stake x decimal odds | Odds calculator |
| What is -150 in decimal, or 5/2 in American? | Odds conversion | Odds calculator |
| What chance does this price imply? | 1 / decimal odds | Odds calculator |
| How much does the book keep on this market? | Sum of implied probabilities – 100% | Odds calculator |
| What does my parlay pay? | Product of the decimal odds x stake | Parlay calculator |
| How much should I bet on the other side to lock in a result? | Payout / odds of the other side | Hedge calculator |
| Can I back every outcome at two books and still profit? | Sum of 1 / best odds below 1 | Arbitrage calculator |
| How much should I stake on a bet with an edge? | (b x p – q) / b, the Kelly criterion | Kelly criterion calculator |
Four of the eight questions are answered by the odds calculator alone; parlays, hedges, arbitrage and stake sizing each need a calculator of their own.
The Three Odds Formats in Ontario
Ontario sportsbooks show American odds by default, and most let you switch to decimal in your account settings. Fractional odds are rare on Ontario boards but common in British coverage and horse racing. They are three ways of writing the same price:
- American, minus (-150): how much you stake to win $100. -150 means $150 to win $100.
- American, plus (+150): how much you win on a $100 stake.
- Decimal (2.50): what $1 returns, stake included. It is the easiest format to calculate with, which is why every calculator converts to it first.
- Fractional (3/2): profit over stake.
| American | Decimal | Fractional | Implied chance | $10 returns |
|---|---|---|---|---|
| -200 | 1.50 | 1/2 | 66.7% | $15.00 |
| -150 | 1.67 | 2/3 | 60.0% | $16.67 |
| -125 | 1.80 | 4/5 | 55.6% | $18.00 |
| -110 | 1.91 | 10/11 | 52.4% | $19.09 |
| +100 | 2.00 | 1/1 | 50.0% | $20.00 |
| +150 | 2.50 | 3/2 | 40.0% | $25.00 |
| +200 | 3.00 | 2/1 | 33.3% | $30.00 |
| +300 | 4.00 | 3/1 | 25.0% | $40.00 |
| +500 | 6.00 | 5/1 | 16.7% | $60.00 |
The longer the price, the lower the implied chance: from -200 to +500 it falls from 66.7% to 16.7%, while $10 returns anywhere from $15.00 to $60.00.
The formulas, if you would rather do it by hand: a minus price converts to decimal as 1 + 100 / odds (-150 = 1 + 100/150 = 1.67); a plus price as 1 + odds / 100 (+150 = 2.50). Decimal back to American: above 2.00, (decimal – 1) x 100; below 2.00, -100 / (decimal – 1).
Payout: Stake Times Decimal Odds
The return on a winning bet is the stake multiplied by the decimal odds; the profit is that minus the stake. On 29 October NorthStar Bets had the Senators at -109 (1.92) away to the Kings. A $25 bet would return $25 x 1.92 = $48.00, a profit of $23.00.
Ontario books round the odds they display, but they pay on the unrounded price, so a payout can differ from your own sum by a few cents. If it differs by more, the price changed between your click and the confirmation – the bet slip shows the price you actually got.
Implied Probability and the Book’s Margin
Divide 1 by the decimal odds and you get the chance the price implies. At NorthStar Bets, the Kings at 1.96 implied 51.02% and the Senators at 1.92 implied 52.08%. Together that is 103.10% – more than 100%, because the extra 3.10% is the book’s margin, built into both prices.
Remove it and you have the fair chances. Scaling the two numbers down to 100% gives the Senators 50.5%. That is the figure to compare with your own view of the game, and it is what our parlay calculator does when you enter both sides of a leg.
The margin is not the same at every book. On the same four games and the same night it ran from about 2.5% to about 7%:
| Sportsbook | Hurricanes – Blue Jackets | Penguins – Mammoth | Lightning – Jets | Kings – Senators | Average |
|---|---|---|---|---|---|
| Pinnacle | 2.7% | 2.5% | 2.7% | 2.5% | 2.6% |
| NorthStar Bets | 3.7% | 3.0% | 2.7% | 3.1% | 3.1% |
| theScore Bet | 3.7% | — | 3.6% | 4.5% | 3.9% |
| BetRivers | 4.2% | 4.3% | 4.3% | 4.2% | 4.2% |
| BET99 | 4.2% | 4.1% | 4.2% | 4.7% | 4.3% |
| Betinia | 4.1% | 4.0% | 4.8% | 4.5% | 4.3% |
| DAZN Bet | 4.1% | 4.0% | 4.8% | 4.5% | 4.3% |
| ToonieBet | 4.1% | 4.0% | 4.8% | 4.5% | 4.3% |
| bet365 | 4.5% | 4.2% | 4.5% | 4.6% | 4.4% |
| Betway | 4.8% | 4.1% | 4.3% | 4.7% | 4.5% |
| FanDuel | 4.6% | 4.6% | 4.6% | 4.6% | 4.6% |
| Betano | 4.7% | 5.3% | 5.3% | 5.0% | 5.1% |
| Swiper | 5.9% | 6.0% | 6.1% | 5.8% | 5.9% |
| BetNova | 6.7% | 6.8% | 6.8% | — | 6.7% |
| Titan Play | 6.7% | 6.8% | 6.8% | — | 6.7% |
Pinnacle had the lowest margin on all four games, and BetNova and Titan Play the highest on the three they listed. Over a season, the difference between a 2.5% and a 7% book is the difference between losing roughly $2.50 and roughly $7 per $100 staked on a two-way market, before any skill. Our moneyline guide compares margins across more games and markets.
Expected Value: Is a Price Worth Taking?
Expected value puts the price and the probability together: the fair chance of a result multiplied by its decimal odds, minus 1. Above zero, the price pays more than the result is worth; below zero, the book’s margin is still inside it. It is the one calculation that tells you whether a bet is good value, rather than whether it wins.
For the fair chance we removed the margin from each book’s two prices and averaged the result across all the books we read, which gives a market view of each game that no single book’s pricing decides. Then we took the best price on each favourite anywhere in Ontario – the Hurricanes and the Lightning, both at home, and the Mammoth and the Senators, both favoured on the road:
| Bet | Fair chance | Best price | Expected value | Per $10 |
|---|---|---|---|---|
| Hurricanes to beat the Blue Jackets, at home | 69.5% | 1.40 (Betway, theScore Bet, BET99) | -2.7% | -0.27 |
| Mammoth to beat the Penguins, in Pittsburgh | 54.7% | 1.80 (Pinnacle) | -1.5% | -0.15 |
| Lightning to beat the Jets, at home | 67.8% | 1.44 (Betway) | -2.1% | -0.21 |
| Senators to beat the Kings, in Los Angeles | 51.5% | 1.92 (NorthStar Bets) | -1.1% | -0.11 |
All four lines are negative: even the best price in the province on each favourite paid less than the result was worth, on average, that night. That is normal.
Best and Worst Prices Against Fair Value
A positive number is rare, small and short-lived, and it is the reason to compare books before each bet. There was none anywhere on the board that night: the best price on each of the eight sides was between about 1% and 3% below fair, and the closest to zero were the Blue Jackets at +225 at ToonieBet, Betinia and DAZN Bet (-0.8%) and the Senators at -109 at NorthStar Bets (-1.1%).
The worst price on the same four favourites was about -5.5% to -7%: the Hurricanes at 1.34 (-294), the Mammoth at 1.71 (-141) and the Lightning at 1.37 (-270) at BetNova and Titan Play, and the Senators at 1.83 (-120) at five books, theScore Bet and Swiper among them – between two and a half and five times further below zero than the best price. Shopping for the best line does not turn betting into a profit, but it is the only habit that makes every bet cost less.
Parlays: Margins That Multiply
A parlay pays the product of its legs’ decimal odds. The example is a four-leg ticket on the four favourites of those games at NorthStar Bets – the Hurricanes 1.38 at home, the Mammoth 1.77 in Pittsburgh, the Lightning 1.43 at home and the Senators 1.92 in Los Angeles – which multiply to 6.71, so $10 would return $67.06.
The margin multiplies too. Each leg loses its few percent, and four legs lose them four times over: on that ticket, the book’s share of the stake was about 11.6%, against about 2.6-3.6% on each leg as a single bet, and every extra leg adds another.
The same four legs would pay $67.50 at Pinnacle, $66.89 at Betway and $59.07 at Swiper – same games, same night: Pinnacle’s ticket would return 14.3% more than Swiper’s, which is 17.2% more profit.
This time the lowest-margin book wrote the best ticket: Pinnacle had the longest price in Ontario on the Mammoth (-125) and was close to the best on the Hurricanes (-255) and the Lightning (-230). NorthStar Bets, with the best price on the Senators (-109) but -265 and -235 on the two home favourites, finished 44 cents behind. Betway, tenth of 15 on average margin, came third because it kept its margin on the underdogs: it had the best prices in Ontario on the Hurricanes (-250, with theScore Bet and BET99) and the Lightning (-225), and the shortest on the Blue Jackets (+200) and the Jets (+185).
The parlay calculator does this for any number of legs, and handles pushes and voided legs.
Hedging: Locking In a Result
A hedge is a bet on the other side of something you already hold. Say the Hurricanes, the Mammoth and the Lightning had won the first three legs of the $10 ticket above and only the Senators were left. It stood to return $67.06. The Kings’ best price that night was 2.03 (+103), at Pinnacle.
To get the same amount whichever team won, you stake the payout divided by the hedge odds: $67.06 / 2.03 = $33.03 on the Kings.
The other three games were scheduled for 7:00 p.m. ET and the Senators game for 10:00 p.m. ET, so this hedge could be placed before the puck drop in Los Angeles, at a pre-game price that may have moved by then; the price above keeps the sum easy to check.
Either way you would end with $67.06 back on $43.03 staked in total – a sure profit of $24.03, instead of a $57.06 profit or the loss of the $10 stake.
The cost is the margin on the hedge bet: at 2.03 the Kings were about 1.6% below their fair price, so the hedge gave up about 52 cents of expected value to remove the risk – $2.24 at Betano‘s -108, the shortest price on the Kings.
A hedge is worth it when the swing matters more to you than that cost. The hedge calculator works out the stake for any ticket.
Arbitrage: Why It Is Rare in Ontario
Arbitrage is rare in Ontario because the best prices across 15 books still added up to more than 100% on all four games we checked. An arbitrage – an “arb” – exists when the best price on each outcome, taken at different books, adds up to less than 100% in implied probability. Back every side in the right proportions and the result is the same whoever wins.
We checked these four games across the 15 books we read, picking the best price on each side wherever it was. None was an arb:
| Game | Best price, home team | Best price, visitors | Combined |
|---|---|---|---|
| Blue Jackets at Hurricanes | 1.40 (Betway, theScore Bet, BET99) | 3.25 (ToonieBet, Betinia, DAZN Bet) | 102.2% |
| Mammoth at Penguins | 2.15 (four books) | 1.80 (Pinnacle) | 102.1% |
| Jets at Lightning | 1.44 (Betway) | 3.05 (NorthStar Bets) | 102.0% |
| Senators at Kings | 2.03 (Pinnacle) | 1.92 (NorthStar Bets) | 101.3% |
Even at the best prices across the market, the books kept about 1.3% in Los Angeles, 2.0% in Tampa and in Pittsburgh, and 2.2% in Raleigh. The closest call was the Senators game: NorthStar Bets‘ -109 on Ottawa and Pinnacle‘s +103 on the Kings added up to 101.3%. Away from the money line, the nearest was the total of 6.5 in Raleigh: the over at Betano (+122) against the under at NorthStar Bets (-130) added up to 101.54% – still above 100%.
Real arbs do appear – usually for minutes, when one book is slow to move a line – and they are small. Ontario operators can also limit the stakes of accounts they consider arbitrage players, as their terms allow, which is the practical ceiling on the strategy. The arbitrage calculator shows how to split the stakes when you do find one.
What No Calculator Changes
A calculator makes the price clear; it does not change it. Every number above has the book’s margin inside it, which means the average result of betting is a loss, and more legs or more bets make that loss larger, not smaller. Use the tools to compare prices and understand a ticket, not as a system.
If you want to set a limit on deposits, losses or time, every sportsbook registered with iGaming Ontario must offer the tools, and our responsible gambling guide explains them. Betting in Ontario is 19+. Free, confidential help is available 24/7 from ConnexOntario at 1-866-531-2600.
Betting Calculator FAQs
How do I calculate how much I will win on a bet?
Convert the odds to decimal and multiply by your stake. That is your total return; subtract the stake for the profit. $20 at -150 (1.67) returns $33.33, a profit of $13.33.
What is +200 in odds?
+200 means a $100 bet wins $200, so it returns $300. In decimal it is 3.00 and it implies a 33.3% chance.
How much is +500 in betting?
A $10 bet at +500 wins $50 and returns $60. In decimal it is 6.00, an implied chance of 16.7%.
What does -110 mean for the book’s margin?
You stake $110 to win $100. In decimal it is 1.91, and it implies a 52.4% chance – the standard price on both sides of a spread or total. The two 52.4% chances add up to 104.8%, so the book’s margin is about 4.8%. Our odds calculator converts any other price the same way.
Do Ontario sportsbooks use American or decimal odds?
American by default, with an option to switch to decimal in the account settings at most books. The price is the same in both formats.
Are betting calculators accurate?
The arithmetic is exact. Small differences from a bet slip come from the book rounding the displayed odds, and larger ones from a price that moved before your bet was accepted.
19+. Ontario only. Gambling can be addictive. Free, confidential help is available 24/7 from ConnexOntario: call 1-866-531-2600, text CONNEX to 247247, or visit connexontario.ca.