How to Calculate Sports Betting Odds

You can’t watch a game on TV right now without JB Smoove, Kevin Hart or Aaron Paul extolling the virtues of various sportsbooks.

Sports betting is undergoing a tremendous explosion in America. Sites like ESPN include betting information on their scoreboards, major newspaper outlets like the New York Times cover it, and betting regularly factors into broadcasts of major sports.

And while there’s an element of luck to sports betting – and any other gambling game – there’s a measure of skill to it as well. The best bettors in games like poker and sports betting have a fundamental understanding of the math behind their bets. 

This allows them to find wagers that have a positive expectation. If you were betting on a coin toss with a friend, the fair price would be even money. You bet $5 on tails, he bets $5 on heads. After 100 flips, you’d be at or reasonably close to 50 heads results, and 50 tails, and you and your friend would have broken even. 

But if someone offered you 2-to-1 odds on tails – that is, they’ll pay you $10 if it lands tails, but you only pay them $5 when it comes heads – you have an excellent bet. After 100 flips, if it landed on tails 50 times, they would pay you $500. The 50 times it came heads, you would pay them $250, for a $250 profit on your end. 

The expected value of that bet is then $2.50. That’s how much you can expect to make, on average, every time you flip that coin.

In sports betting, the numbers might be a bit more complicated, but the idea is the same. Find bets with a positive expected value. Bet them enough, and you can expect to stack up wins in the long run.

To do that, though, you need to work through the math. The betting tools at a site like Unabated Sports can help you.

Odds Converter

If you’re betting in the United States, bets are typically expressed in American odds. That is, based around a $100 unit, with negative numbers showing a bet that pays less than even money, and positive numbers pay more. A bet of -110 means you have to bet $110 to win $100 (or $22 to win $20, etc.). A bet of +120 means you win $120 if you bet $100.

If you’re used to other odds representations like decimal or fractional, you can use the Odds Converter to see what those numbers look like in other forms. Including implied probability, which is a crucial concept for any bettor. A bet at +100 has an implied probability of 50% – the fair price on our coin toss that can come heads or tails. A bet at -110 has an implied probability of 52.4%. 

Making bets that have a higher likelihood of happening compared to their implied probability is at the heart of plus-EV wagering. If you can bet that the sun comes up tomorrow at -110, you’ve found a bet that has a 100% chance of happening mispriced like it only has a 52.4% chance. 

No-Vig Fair Odds Calculator

Why -110? That extra “10” is the house edge, or vig. Sportsbooks bake in an extra fee to bet with them. It’s the main advantage they have; the way they make money. If you want to really find true implied probability, you need to remove the vig from a bet. On an NFL spread, each bet is typically -110 on each side. The book is saying “It’s 50/50 the Cowboys -3 wins or loses. But by baking in the extra juice, we’re going to win no matter what.”

Use the No-Vig Fair Odds Calculator to find out what the “fair” prices of a bet are, and what implied probability those numbers represent.

Compare Lines Calculator

Say you have two lines at two different sportsbooks for an NFL game: y Minnesota -3 (at -105) or -2.5 (-110). Which one is better? In the first, you only have to bet $105 to win $100. The second is $110 to win $100. What’s the value of that half a point?

You can use the Compare Lines Calculator to find out that -2.5 is the better line despite the higher price. The true equivalent of a -3 line to -2.5 would be -2.5 (-125). At -2.5 (-110), you’re getting a bet that should “sell” for $125 for only $110 – a major bargain.

Other Calculators:

There are other, more advanced calculators at Unabated to help you navigate the world of sports betting. These may include a Closing Line Value Calculator, an Alternate Lines Calculator, a Partial Game Derivative Calculator for figuring fair first half or first quarter prices based on full game numbers. There is a Hedge Betting Calculator to see if you should buy insurance on potentially high-risk, high-reward bets. And a Hold Calculator for those of you interested in playing futures markets like who will win the Super Bowl or College Football National Championship.

Sports betting isn’t entirely a sports game. It’s a math game, and you need the right tools to beat it.