Trans4mind Home Page
Home Article Library Gaming, Casinos & Gambling

Getting into Gambling? Here's How to
Understand Betting Odds


In May of 2018, the Supreme Court struck down a 1992 federal law that prohibited sports betting.

This action has given the states the green light to legalize and regulate sports betting as they see fit.

As a result, many states have already legalized sports betting and many more are looking to follow suit.

As sports betting was illegal in most places, many new-timers don't know how to understand betting odds. So if you haven't had to determine probability since your high school math class, now is a great time for a refresher!

How to Understand Betting Odds

All gambling boils down to figuring out how to bet on the odds which are most in your favor. Whether you're rolling dice or looking up ice hockey odds, it's all about betting in your favor.

And to do that, the first thing you have to know is how to understand probability.


For any given event, there are a set number of outcomes. If you flip a coin, one of two outcomes will result. If you roll a die, one of six outcomes.

Gambling is just predicting which outcome will result. If you bet on heads in a coin toss, you have a 50% chance of winning. Bet on six in a dice roll and you have about a 16.67% chance of winning.

In sports betting, you would see these odds rendered in plain numbers. For example, that coin toss, the 50/50 odds would be rendered as -100. If the odds were 2/3, or a 66.67% chance of success, then it would be rendered as -200, and so on.

The reason why these numbers are rendered as such is because of what's called the vig.

The Vig

The above numbers represent just pure probability, but in sports betting though the odds are a little more complicated. For example, the odds of a wager usually add up to more than 100%.

Look at the odds on the 2019 Superbowl. The Patriots had an implied 57.4% chance to win, while the Rams had an implied 46.5% chance to win. That adds up to a total of 103.9%.

The added percentage is called the vigorish, or vig. It's essentially a fee that bet-takers exact and is a significant juncture in sports betting.

The vid is factored into how much money you have to bet to win a certain amount in return. Going back to the Superbowl, if someone were to bet on the Patriots to win, they would have to bet $135 to win $100 because of the vig. Another gambler might bet $100 on the Rams in order to win $115.

In this scenario, there is a difference of $20 left on the table that the sportsbook makes if the underdog wins. Meanwhile, the book stands to lose nothing if the favorite wins. So for this scenario, the vig is $20.

The easiest way to figure the vig is to take the amount that you would risk betting on a favorite to win $100, take the amount that you would win betting $100 on an underdog, and then split the difference.

May the Odds be Ever in Your Favor

At a glance, all the spreadsheets of opaque numbers can make learning how to understand betting odds look like more trouble than it's worth. But at its core, it's just basic math.

Learning to figure the odds lets us determine the implied probability of an outcome and how much money you stand to make if that outcome happens.

Once you're comfortable reading the odds, it becomes second nature.

Sports betting can be an exciting way to win a little money while exercising your brain. But it's just one skill that you can learn to help enrich your mind and your wallet.

For more ways to grow and improve yourself, be sure to visit the Trans4mind article archives.

More Gaming, Casinos & Gambling articles
You'll find good info on many topics using our site search: