How Do Betting Odds Work? An Alberta Guide

How do betting odds work when one sportsbook screen shows -150 and another shows 1.67 for the same price? Both are one number in two formats, and the minus sign in the American format is where most confusion starts. This guide converts the three formats, turns them into implied probability and works through the operator margin with hypothetical numbers. Odds are a price, not a forecast or a route to income.

How American, Decimal and Fractional Odds Show the Same Price

American odds use $100 as the reference point: a minus number is what you stake to win $100, and a plus number is what a $100 stake wins. Decimal odds show the total return for each $1 staked, stake included. Fractional odds show the win relative to the stake.

On a hypothetical $20 stake, -150 returns $33.33 in total ($13.33 won plus the stake) and +130 returns $46.00 ($26.00 won plus the stake). Decimal odds also make a combined price easier to follow, which helps once you look at what a parlay is. To convert between formats:

• Minus American to decimal: add 1 to 100 / the number without its sign.
• Plus American to decimal: add 1 to the number / 100.
• Decimal of 2.00 or more to American: (decimal – 1) times 100, with a plus sign.
• Decimal under 2.00 to American: -100 / (decimal – 1).
• Decimal to fractional: decimal – 1, written as a fraction.

Moneyline Bets Explained with Hypothetical Hockey Prices

A moneyline bet, explained in one line, is a bet on which side wins the game, with no goal or point spread. In a hypothetical hockey game with Team A at -150 and Team B at +130, Team A is the favourite: the minus sign shows it costs more to win the same amount. Team B is the underdog. What the two signs tell you:

• A minus price means you stake more than you would win.
• A plus price means you would win more than you stake.
• A price of +100 means the stake and the win are equal.
• Neither sign tells you which team will win.

Whether a hockey moneyline includes overtime and the shootout is set in each sportsbook's Alberta house rules, which is why how to bet on hockey treats settlement as a separate check.

Over/Under Betting Explained with a Half-Point Total

Over/under betting, explained simply, is a bet on whether the combined score lands above or below a number the sportsbook sets, also called a total. In a hypothetical hockey total of 5.5 goals with both sides at -110, a game with six or more goals settles the over and a game with five or fewer settles the under.

The half point removes the case where the score lands exactly on the line. With a whole-number line, how an exact landing is settled varies by sportsbook, so check that sportsbook's Alberta rules.

How Implied Probability Turns Betting Odds into a Percentage

Implied probability is the price written as a percentage: 1 divided by the decimal odds. For American odds, a minus price converts as the number divided by the number plus 100 (150 / 250 = 60.00%), and a plus price converts as 100 divided by the number plus 100 (100 / 230 = 43.48%).

We calculated these figures from the formulas above, rounded to two decimals. Add the implied probabilities on every side of one market and the total comes out above 100%: that excess is the operator margin.

Operator Margin (Overround) in a Worked Odds Example

The margin, also called the overround or vig, is how far a sportsbook's prices sit above a fair pair. Using the hypothetical moneyline above, the table shows our calculation, with the margin removed by scaling both sides back to 100%.

The 3.48 percentage points above 100% are the overround. With stakes on the two sides in proportion to their prices, the sportsbook keeps about 3.36% of the money staked whichever team wins. For the bettor, a $100 stake on either team has an expected result of about -$3.36 if the margin-free percentages were the true chances. A -110 price on both sides works the same way:

• Each side converts to 52.38% implied probability.
• Together the two sides add up to 104.76%.
• A winning $100 stake at -110 returns $190.91 in total.
• At a true 50% chance, the expected result is -$4.55 per $100.

Why Betting Odds Are a Price, Not a Forecast

A price of -150 does not mean Team A wins 60% of the time. It means the sportsbook charges a price that converts to 60%, margin included. Two sportsbooks can price the same game differently, and a price can change before the event starts. None of that makes it a prediction. What the price leaves out:

• The margin sits inside every price in the market.
• A favourite at -150 still loses some games.
• An underdog at +130 still wins some games.
• No price tells you which result will happen.

What Registered Alberta Sportsbooks Show for Odds

We checked which sportsbook brands appear on AGLC's list of gaming registrants and in the AiGC directory of registered sites as of October 28, 2026. Ten brands registered in the iGaming operator class carry "Sportsbook" in their registered name, and other registered brands may also take sports bets. Each is registered with AGLC and operates under an agreement with the Alberta iGaming Corporation.

The default format, and whether you can switch it, varies by sportsbook, so check the settings on its Alberta site; the formulas above work in any format. AiGC's player FAQ says you must be 18 or older and physically located within Alberta's borders to bet on a regulated site. The rules behind the legal gambling age in Alberta are covered separately.

Why Betting Systems and Streaks Do Not Change the Expected Result

A betting system changes the stake, not the price. Here is a hypothetical doubling system on -110 bets, starting at $10 and doubling after every loss:

Every one of those bets carries the same expected result, about -4.55% of its stake at -110 on a 50% chance. Across $310 staked, that is about -$14.09, and doubling only makes the total staked climb faster. A streak does not change the margin in the next price or make the next result more or less likely.

Responsible Gambling Tools for Sports Betting in Alberta

AiGC's player FAQ says regulated sites let you set deposit, loss and session-time limits in the account's responsible gaming or settings area. It describes self-exclusion as free and voluntary, arranged through AGLC's centralized portal, and blocking all regulated Alberta iGaming sites and land-based casinos for a set period. Habits that keep betting a paid entertainment:

• Set a deposit limit before the first bet.
• Decide in advance how much you can afford to lose.
• Never raise stakes to recover a loss.
• Take breaks, and treat not betting as a normal choice.

According to AiGC, free and confidential support is available around the clock through 211 Alberta. Limits, self-exclusion and where to get help are set out in responsible gambling in Alberta.

What Betting Odds Mean for Alberta Bettors

Betting odds are one price written three ways, and any format converts into implied probability. The sides of a market add up to more than 100%, and that excess is the margin: in our hypothetical examples, about $3.36 to $4.55 per $100 staked. Odds are not a forecast or a source of income. When comparing sports betting sites in Alberta, check the registration, the settings and your limits.