Written by Clay Smith
Of course, betting the New York Yankees at -1.5 to bring down the odds from -190 to -110 isn't too fun when they win 4-3 and you don't cash a bet. Betting on the point spread is the most. 'What does 5 to 1 odds imply?' Here we'll inform you what 5 to 1 odds mean, what 5 to 1 probability means, and present you what a 5 to 1 odds payout can be. Every time you toss an unbiased coin, it's all the time a 50/50 likelihood. If the coin lands on heads 11 occasions, the odds. For example, betting on a market priced at 2.5 means you would win two and a half times your stake if your bet were to win. This means you'd win $2.50 for every $1 you wager. Another example of decimal odds in action would be betting on NHL game with odds of 9.0.
Idiot's Guide
That's right - I will be your guide. The good thing about having an idiot for a guide is that I have to make it simple to understand it myself, which means, hopefully, you will understand it as well.
Probability or Odds
Probability
Probability means the risk of an event happening divided by the total number of people at risk of having that event. I will use the example in a recent JAMA article. In a deck of 52 cards, there are 13 spades. So, the risk (or probability) of drawing a card randomly from the deck and getting spades is 13/52 = 0.25 = 25%. The numerator is the number of spades, and the denominator is the total number of cards.
Odds
Odds seems less intuitive. It is the ratio of the probability a thing will happen over the probability it won't. In the spades example, the probability of drawing a spade is 0.25. The probability of not drawing a spade is 1 - 0.25. So the odds is 0.25/0.75 or 1:3 (or 0.33 or 1/3 pronounced 1 to 3 odds).
Moving back and forth
To go from odds to probability, simply take the numerator/(denominator + numerator). In the spades example, the odds of 1/3 is converted by taking 1/1+3 = 0.25 - and now we are back to probability. To go from probability to odds, simply take the numerator/(denominator-numerator). In the spades example, given that the probability of drawing a spade is 1/4, take 1/(4-1) = 1:3 odds or odds = 0.33.
Statistical Significance
If an odds ratio (OR) is 1, it means there is no association between the exposure and outcome. So, if the 95% confidence interval for an OR includes 1, it means the results are not statistically significant. Example, exposure to colored vs white Christmas lights was associated with an increase in jocularity score, OR = 1.2 (95%CI 0.98-1.45). Sorry, this is not statistically significant. Let's just go with white lights…
Use
Either the OR or risk ratio (RR) could be used in many study types. However, only the OR can be used in case-control studies. Because in order to calculate the RR, one must know the risk. Risk is a probability, a proportion of those exposed with an outcome compared to the total population exposed. This is impossible in a case-control study, in which those who already have the outcome are included without knowing the total population exposed.
Risk Ratio
RR is a very intuitive concept. It is the probability (or risk) of one outcome over the probability (risk) of another. Let's use a study we covered on JF to discuss this concept. Survival was lower in pediatric patients intubated during arrest compared with those not intubated: 411/1135 (36%) vs 460/1135 (41%). So, the RR is 36.2%/40.5% = 0.89. This means survival was reduced by a factor of 0.89 for pediatric arrest patients who were intubated during arrest vs. those who were not. As an example, if survival was expected to be 40%, then intubating during arrest would reduce it to: 40% x 0.89 = 35.6%.
Let's do one more example. Supination-flexion (SF) vs hyperpronation (HP) to reduce nursemaid's elbow was more likely to fail. The risk of failure with SF was 96/351 (27%) vs. 32/350 (9%) with HP. The RR was 3. This has a very intuitive meaning: risk of failure with SF was three times more likely than HP.
Odds Ratio
The OR is a way to present the strength of association between risk factors/exposures and outcomes. If the OR is <1, odds are decreased for an outcome; OR >1 means the odds are increased for a given outcome. Let's look at the examples again and consider odds.
For pediatric arrest, the risk of survival if intubated during arrest was 411/1135 (36%) vs 460/1135 (41%) if not intubated. Let's convert to odds and calculate an OR.
Intubated: 411/1135-411 = 411/724 = 0.57 odds.
Non-intubated: 460/1135-460 = 460/675 = 0.68 odds.
So, the OR is 0.57/0.68 = 0.83.
Note, this is very close to the RR (0.89) but is a slight overestimate of the effect on the outcome. This is always the case with the OR compared to the RR - it overestimates the effect.
Take the example of supination-flexion vs hyperpronation for nursemaid's. The risk of failure for SF was 96/351 vs. 32/350 with HP. Let's convert this to odds.
50 1 Odds Payout
SF: 96/351-96 = 0.376 odds
HP: 32/350-32 = 0.10 odds
The OR is 0.376/0.10 = 3.7
Note, the OR overestimates the RR, which was 3. Although one could say the risk of failure using SF is 3 times greater than HP, one could not say, based on the OR, the risk was 3.74 times greater. The OR and RR are not the same. What could be said is that the odds of failure is 3.74 times greater.
Risk Ratio vs Odds Ratio
Whereas RR can be interpreted in a straightforward way, OR can not. A RR of 3 means the risk of an outcome is increased threefold. A RR of 0.5 means the risk is cut in half. But an OR of 3 doesn't mean the risk is threefold; rather the odds is threefold greater. Interpretation of an OR must be in terms of odds, not probability. Again, the OR will always be an overestimate compared to the RR. However, the RR and OR will be similar for rare outcomes, <10%. But the OR increasingly overestimates RR as outcomes exceed 10%. This is easier to understand with an example.
Pretend a new vape, Vapalicious, is associated with cancer.
80/100 people who use it get cancer.
20/100 who don't use it get cancer.
The risk of getting cancer is 4 times greater in Vapalicious users. RR = 0.8/0.2 = 4
Note how distorted the OR becomes in this example. OR = (80/20)/(20/80) = 16
What if Vapalicious rarely caused cancer?
5/1000 get cancer with Vapalicious vs 2.5/1000 for non-users.
RR = 2.
OR = 2 as well (actually 2.005)
With rare outcomes, the RR and OR are very similar.
Why Does This Matter?
This matters because we often equate the OR and RR. Unwary researchers, reviewers, or news media might report a 16-fold increased risk of cancer from Vapalicious. In fact, there was a 4-fold increased risk of cancer from Vapalicous. Not that I plan to use Vapalicious (or any other vape), but a 16-fold vs 4-fold increase is a gross overestimation of the effect.
What Does the OR Mean?
So, what does an OR mean? Here it is in plain language.
An OR of 1.2 means there is a 20% increase in the odds of an outcome with a given exposure.
An OR of 2 means there is a 100% increase in the odds of an outcome with a given exposure. Or this could be stated that there is a doubling of the odds of the outcome. Note, this is not the same as saying a doubling of the risk.
An OR of 0.2 means there is an 80% decrease in the odds of an outcome with a given exposure.
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Summary
Odds Ratio is a measure of the strength of association with an exposure and an outcome.
OR > 1 means greater odds of association with the exposure and outcome.
OR = 1 means there is no association between exposure and outcome.
OR < 1 means there is a lower odds of association between the exposure and outcome.
If the 95% confidence interval for the OR includes 1, the results are not statistically significant.
OR and RR are not the same.
OR always overestimate RR, but…
OR approximates RR when the outcome is rare but markedly overestimates it as outcome exceeds 10%.
References
The odds ratio by Bland and Altman, of Bland-Altman plot fame
Wikipedia aka source of all statistical knowledge
Understanding how to read odds is crucial to betting on sports. This guide will teach you how to read odds for moneyline, total, and spread bets. We will be looking at American, decimal, and fractional odds, which are three different ways of writing the same odds.
What are Odds?
Odds represent the likelihood of an outcome occurring. In sports betting, each team is assigned odds that represent the likelihood of them winning the game. When the odds for two teams are even, meaning 1 to 1, it means that each team is equally as likely to win the game. If Team A is assigned 2 to 1 odds, it means Team B is twice as likely to win. If Team A is assigned 10 to 1 odds, it means Team B is ten times as likely to win.
Odds are typically expressed with a positive or negative sign in front of them and are not written as 2 to 1 or 3 to 1.
How do Plus and Minus Odds Work?
In a betting line between two teams, the team expected to win, or favorite, will have minus or negative odds. This means for every dollar wagered, you will earn less than a dollar if your bet wins. The team expected to lose, or underdog, will have positive or plus odds. This means for every dollar you wager, you will gain more than a dollar if your bet wins.
The table below shows an NHL game where the Boston Bruins are favorited to beat the St. Louis Blues.
| Team | Odds | Amount Wagered | Total Payout |
|---|---|---|---|
| Boston Bruins | -150 | $1 | $1.67 ($1 bet + .67 cent won) |
| Boston Bruins | -150 | $10 | $16.67 ($10 bet + $6.67 won) |
| St. Louis Blues | +130 | $1 | $2.30 ($1 bet + $1.30 won) |
| St. Louis Blues | +130 | $10 | $23 ($10 bet + $13 won) |
American Odds
American odds are what you will see displayed on almost every sportsbook. Just like the metric system, dates, and miles per hour (mph), Americans do things differently when it comes to betting odds. Take a look at this standard slate of betting odds from for an MLB game.
| Team | Spread (Runline) | Moneyline | Total |
|---|---|---|---|
| Chicago White Sox | +1.5 (-115) | +140 | Over 9.0 (-120) |
| Los Angeles Angels | -1.5 (-105) | -120 | Under 9 (-105) |
The first thing you will notice when reading odds will be that:
- Odds have either a plus or minus in front of them
- Odds are in terms of 100
Betting Odds are written in terms of 100 as an industry standard. The easiest way to think of the plus and minus signs is as follows. If it is a plus, you will receive more than a $100 payout on a $100 bet. If it is a minus, you will have to bet more than $100 to win a $100 payout.
Thankfully, you can view your potential winnings on each bet before placing it at an online sportsbook. That said, it is beneficial to understand the betting odds.
Moneyline Bets
Definition of bet: A moneyline bet is a wager on which team will win the game outright. Both the favorite and the underdog are given odds to win the game. Read the chart below to get started on reading odds for the following game:Green Bay Packers (-150) vs. Detroit Lions (+130)
| Moneyline Odds | How to Read it | What it Means |
|---|---|---|
| Lions +130 | Lions plus 130 | By betting $100 you will win $130 if the Lions win |
| Packers -150 | Packers minus 150 | To win $100, you must wager $150 on the Packers to win |
Spread Bets
Definition of bet: A spread bet is a wager on which team will cover the spread or point spread.
How to read spread odds for the following game: Los Angeles Lakers +5 (-110) vs. Houston Rockets -5 (-110)
| Spread Odds | How to Read it | What it Means |
|---|---|---|
| Lakers + 5 (-110) | Lakers plus 5 points at minus 110 odds | The Lakers must win the game, or lose by less than 5 for you to win your bet |
| Rockets -5 (-110) | Rockets minus 5 points at minus 110 odds | The Rockets must win the game by more than 5 points for you to win your bet. A tie is a push, meaning you don't win or lose. |
Total (Over/Under) Bets
Definition of bet: A total bet focuses on how many points are scored, regardless of who wins the game. After a total point score has been set, bettors can wager on whether the actual score of the game will be over or under the set point score.
How to read over/under odds for the following game:
New York Yankees vs. Boston Red Sox Over 7 (-115) Under 7 (-110)
| Total Odds | How to Read it |
|---|---|
| Over 7 (-115) | In order to win $100, you must bet $115 on the overall combined run score to be higher than 7 |
| Under 7 (-110) | In order to win $100, you must wager $110 on the total combined run score to be less than 7 |
Keep in mind for both spreads and totals that if the game ends in a draw for the bet (Yankees 4, Red Sox 3), then you get your bet back but do not win or lose any additional money.
Fractional Odds
Fractional odds are used more commonly in parts of Europe, as well as in horseracing. To calculate fractional odds, you have to do some mental division or enter your desired amount and see what the sportsbook shows as your payout! Here are some odds for a fictitious horse race and how you go about reading them.
| Horse Name | Odds | How to Read it | Your Bet | You Win |
|---|---|---|---|---|
| Laser Focus | 15/1 | Fifteen to one | $10 | $150 |
| American Pride | 7/2 | Seven to two | $10 | $35 (10 x 3.5) |
| Green Eggs | 3/5 | Three to five | $10 | $6 (10 x .6) |
In this race, where we only have three horses, you can see Laser Focus is the underdog, while Green Eggs (no ham) is the favorite. A lot of sportsbooks offer a fractional view if you prefer it to the American odds.
Decimal Odds
Decimals odds are used more commonly in parts of Europe. When using decimal odds, the underdog has the higher of the two numbers, while the favorite has the lower of the two. To calculate decimal odds, you can use the following equation.
Return = Initial Wager x Decimal Value
Example: Let's say the Arizona Diamondbacks 2.00 are playing the Chicago Cubs 1.90
| Team | Your Bet | Your Return | Your Profit |
|---|---|---|---|
| Arizona 2.00 | $1 | $2 | $1 |
| Chicago 1.90 | $10 | $19.09 | $9.09 |
A lot of sportsbooks offer a decimal view if you prefer it to the American odds.
In conclusion, American odds are almost always displayed at any United States sportsbook, while fractional and decimal odds are almost always displayed at any sportsbook outside of the United States. Check out our Guides Page to see where sports betting stands in your state!
Why do Odds Matter in Sports Betting?
The odds are essential when selecting a sportsbook because they affect your money. If you choose a sportsbook with poor odds, you will end up wasting money every time you place a bet. Let's say you bet $10 on the Vikings moneyline at -200 at one sportsbook. If you win your bet, you pocket $5. If you went line-shopping and found the same bet for -175 at another sportsbook, you would pocket $6, $1 more. Understanding betting odds allows you to decipher between good and bad odds.
Look at the odds below offered on five games from the 2019 NFL Season. Odds from five different sportsbooks are shown. You'll notice each sportsbook offers different odds for each game. If you were betting on these games, you would be able to find the best odds for your desired bets. Using this strategy of line shopping will allow you to save money while betting on games.
How to Use Odds to Calculate Implied Probability
Odds can be used to calculate the implied probability of a team winning or losing a game. You can use a simple math equation to understand what the sportsbook thinks the probability of each team winning is. For positive odds, probability = 100/(odds + 100). For negative odds, probability = odds/(odds – 100).
| Team | Odds | Implied Odds of Winning | Implied Percentage |
|---|---|---|---|
| Miami Heat | +130 | 100/(130 + 100) = .4347 | 43.47% |
| Chicago Bulls | -110 | -110/(-110 - 100) = .5238 | 52.38% |
If you think the Chicago Bulls have a 70% chance of winning, then betting on them would be considered a smart bet.
The process is simple, but If you don't feel like doing the math, use ESPN's gamecast preview: preview or Action Network's odds calculator.
Odds FAQ
What does a negative point spread mean?
In a professional sports matchup a point spread is given to each team for sports betting purposes. When a negative point spread is given to a team, it means they are favorited to win the game. When a positive point spread is given to a team, it means they are not expected to win the game.For example, if the Kansas City Chiefs are minus three (-3) against the Los Angeles Rams (+3), then it is expected that the Kansas City Chiefs will win the game and that Los Angeles will lose.
What do odds of +200 mean?
Odds of +200 mean 2 to 1. For every $1 wagered on a team with +200 odds $2 will be paid out. Odds of +200 are greater are offered on teams that are NOT expected to win a game.
How do parlay odds work?
A parlay bet is a group of spread, moneyline, or total bets combined into one bet to increase the payout odds. In order for the parlay to win, each separate bet has to win. Parlay odds offer bigger payouts than normal odds because they are riskier since each individual bet has to win.
Here is an example of a standard parlay payout table based on true odds. What this means is exact payouts are shown for wagers at -110 odds, where a bet of $110 wins you $100.
| Parlay Size | Payouts |
|---|---|
| 2-Team | 2.645/1 |
| 3-Team | 5.958/1 |
| 4-Team | 12.283/1 |
| 5-Team | 24.359/1 |
| 6-Team | 2.645/1 |
| 7-Team | 91.424/1 |
| 8-Team | 175.446/1 |
| 9-Team | 335.852/1 |
| 10-Team | 642.082/1 |
| 11-Team | 1226.701/1 |
| 12-Team | 2342.793/1 |
Methodology
For the BettingBuck.com annual best online sportsbooks review published in 2020, a total of 2,300 data points were collected over six months and used to score sportsbooks. Additionally, odds data was collected for each sportsbook on over 1,400 bets to give each sportsbook a comparative odds ranking.
Sports betting sites were scored across seven core categories to computer an overall rating: total number of sports and bets offered, odds, live betting features, mobile apps, educational resources, ease of use, and current bonuses.
What Does 3/5 Odds Mean
Learn more about how we test.