How to Bet on Sports:
The (almost) Complete Sports Betting Guide
Being a profitable sports bettor may be tough, but it's within reach. This guide will walk you through the essentials and get you started in the right direction.
Updated 27 February, 2014
Table of Contents
- Before You Start
- The Basics
- Being Profitable
- Where to Bet
- How Much to Bet
Before You Start
Figure out if Sports Betting is a Mistake
Sports betting is a tough pickle to conquer. It's not as profitable, as easy or as sexy as the movies make it seem. If you're not careful it can be filled with unwanted emotional roller coaster rides. Going on tilt even once in several years is enough to destroy you.
If you are prone to addiction, sports betting will probably get the best of you at some point and you will damage relationships with your family and your friends. Even if you have no addiction problems and are a profitable bettor you are still likely to face alienation thanks to the fact that sports betting lies outside the realm of the socially acceptable.
And if all that's not bad enough, betting on sports may not be legal - or may be of questionable legality - in your jurisdiction.
Decide What Kind of Sports Bettor You Want to Be
Is your main interest to make money or is your main interest to have fun? Either is fine so long as you embrace it.
You can either be the kind of bettor who does a ton of research, bets conservatively, doesn't get any thrill out of the game and expects to yield a small return in the long run, or you can be the kind of bettor who watches each possession on the edge of his seat as his heart pounds faster and faster with the seconds ticking off the clock.
You can't have it both ways.
Don't lie to yourself, because it will end in disaster. If you don't know which category you fall into then you probably fall into the thrill-seeking category. If any of your losing bets has ruined your night then you're in the thrill-seeking category. If you're the kind of guy who likes to play 14 hours of poker at a time to come out $5 ahead then you're probably in the thrill-seeking category.
How to Read Lines
All bets have a moneyline which tells you the ratio of how much you have to bet to win a certain amount. Some other bet types - most notably spreads and totals - have additional information in the line which will be discussed in the next section. When it comes to moneylines there are two common odd formats: American Odds and Decimal Odds. Just like with our refusal to adopt the metric system, America has decided to embrace the more confusing of the two formats. There is also the Fractional Odds format which is the most popular for horse racing but the least popular for sports betting. We'll skip that one.
New York Yankees -140 vs Boston Red Sox +130
When reading American lines, a negative number indicates a favorite - an event that has greater than a 50% chance of occurring. A positive number indicates an underdog - an event that has less than a 50% chance of occurring.
A favorite event is read as "Risk X to win 100". So in our example above you would read the -140 New York Yankees line as "Risk 140 to win 100".
An underdog event is read as "Risk 100 to win X". In our example you would read the +130 Boston Red Sox line as "Risk 100 to win 130".
Of course you don't always have to bet in increments of $100. Those numbers just set the ratios for you. eg, if you wanted to bet $20 on the Red Sox then you would be risking $20 to win $26.
New York Yankees 1.714 vs Boston Red Sox 2.3
Decimal Odds are displayed as the total that you will return - your original stake plus your win amount - from a $1 bet. To get just the win amount simply subtract 1 from the line. So the Yankees line reads "Bet 1 to return 1.714" or "Bet 1 to win 0.714". The Red Sox line reads "Bet 1 to return 2.3" or "Bet 1 to win 1.3".
Notice how that was a lot easier to explain than American Odds?
Calculating Implied Win Rate
It's great to know how much you'll win for a given bet size, but if you're a serious sports tipster looking for an edge then you'll also need to know how often you'll have to win to make a bet profitable. Luckily that's pretty easy.
Calculate Implied Win Rate with American Odds
To calculate a win percentage from a favorite line the formula is
win-rate = [-line / (100 - line)]. So the Yankees probability of winning is
[140 / (100 + 140)] =
58.3%. The win percentage formula for the underdog is
[100 / (100 + line)]. So the Red Sox probability is
[100 / (100 + 130)] =
If you noticed that 58.3% + 43.48% adds up to more than 100% then you're absolutely right. It does. And that extra percentage is how the sportsbooks make their money. In the Calculating the No-Vig Line section we'll go over how to take the juice out of the equation.
Calculate Implied Win Rate with Decimal Odds
Ahh, thank you Decimal Odds for your simplicity. Calcuting the win percentage from Decimal Odds - regardless of favorite or underdog is as easy as
win = [1 / line]. So using our above example the Yankees would be
[1 / 1.714] =
58.3% and the Red Sox are
[1 / 2.3] =
Converting Between Lines
Convert American Odds to Decimal Odds
For negative/favorite odds the formula is
decimal = [(100/-line) + 1] so the Yankees line becomes
[100/140 + 1] =
For positive/underdog odds the formula is
decimal = [line/100) +1] so the Red Sox line becomes
[130/100 + 1] =
Convert Decimal Odds to American Odds
If the line is < 2 (eg a favorite) the formula is
line = [(-100) / (decimal - 1)] so the Yankees line becomes
[(-100) / (1.714 -1)] =
If the line is >= 2 (eg an underdog) the formula is
line = [(decimal – 1) *100] so the Red Sox line becomes
[(2.3 – 1) *100] =
Calculating the No-vig Line
Using the standard lines to calculate necessary win percentages is problematic because those standard lines have the bookmaker's vigorish/juice built into them and thus aren't a real representation of the "fair" line. With a little math we can take that juice out and get the no-vig lines. We must first get the implied win rate for both lines and then we can use them to get the no-vig win probabilities and finally to get the no-vig moneylines. We've already calculated the implied win rates above, so we'll use those numbers here.
Calculate No-vig Line with American Odds
For negative/favorite odds the no-vig win rate formula is
no-vig-win-rate = [wF / (wF + wU)] where
wF = implied win rate of the favorite and
wU = implied win rate of the underdog so the no-vig win rate for the Yankees =
[.583 / (.583 + .435)] =
57.3%. We can then convert that win rate to a moneyline to get the no-vig moneyline. The formula to convert a percentage to a moneyline for a favorite is
line = [-100w / (1 – w)] =
[-100(.573) / (1 – .573)] =
For positive/underdog odds the no-vig win rate formula is
no-vig-win-rate = [wU / (wF + wU)] where
wF = implied win rate of the favorite and
wU = implied win rate of the underdog so the no-vig win rate for the Red Sox =
[.435 / (.583 + .435)] =
42.7%. We can then convert that win rate to a moneyline to get the no-vig moneyline. The formula to convert a percentage to a moneyline for an underdog is
line = [(100 – 100w) / w] =
[(100 - 100*.427) / .427] =
Alas the no-vig "fair" line for this game is Yankees -134 vs Red Sox +134
Calculate No-vig Line with Decimal Odds
Just like with American Odds we'll first use the implied win percentage to find the no-vig win percentage. Since that is the same regardless of line format, we can carry over that the Yankees have a .573 chance of winning and the Red Sox have a .427 chance.
Converting a win percentage into a Decimal Line is done with the formula
line = [1/win] so the Yankees no-vig line is
[1 / .573] =
1.75 and the Red Sox no-vig line is
[1 / .427] =
The Different Types of Bets
The moneyline is a bet on a team to win straight up and is the bet style outlined in all of the examples in the previous section. If the team wins then your bet wins. If the team loses then your bet loses. It's the simplest type of bet possible. All bets have a moneyline associated with them, but Moneyline bets are the only ones that don't have other lines associated with them.
Point Spread (aka runline in baseball, puckline in hockey)
A point spread is a bet that compensates for disparities in the teams playing by applying a handicap that tries to make both teams have close to an equal chance of winning the game after the handicap is applied. If you bet on the favorite then the favorite has to win by more than the handicap for your bet to win. If the favorites wins by exactly the handicap then your bet is a push and your wager is refunded. If you bet on the underdog then the underdog has to either win or they have to lose by less than the handicap for you to win your bet. If they lose by exactly the amount of the handicap then your bet is a push and your wager is refunded. Point spreads often end in half points - eg 7.5 - which makes a push impossible.
- Green Bay Packers -3.5 -101
- Minnesota Vikings +3.5 -109
In the example above the Packers are the favorites and the Vikings are the underdogs. Note that the moneylines (the payouts) on point spreads do not have to be equal for both teams. In this case a bet on the Packers offers a slightly more favorable return.
Total (aka Over/Under)
A Total bet - sometimes called an Over/Under bet - is a bet on the total number of points/runs/goals in a game. If the total is 208 points in a basketball games, for example, then the Over wins if more than 208 total points are scored between both teams and the Under wins if less than 208 combined points are scored. If exactly 208 points are scored then the bet is a push and your wager amount is refunded. Totals often end in half points - eg 208.5 - which makes a push impossible.
A parlay is a single bet compromised of two or more individual bets. If any of the individual bets loses then the parlay loses. Thus parlays are more likely to lose than individual bets but they offer greater payouts.
In theory the odds of a parlay are calculated by multiplying the Decimal Odds of each individual bet in the parlay. In practice some sportsbooks will make parlay lines less favorable by reducing the payouts. Here's a theoretical 3-team parlay:
- Bet 1: Philadelphia Eagles -3 1.50 (-200)
- Bet 2: Orlando Magic +1.5 1.91 (-110)
- Bet 3: Montreal Canadiens 2.40 (+140)
- Parlay Odds = 1.5 * 1.91 * 2.4 = 6.876 (+588)
To make things easier you can use this parlay calculator.
There are variations of the above, like futures, team totals, 1st or 2nd half bets, props, teasers, etc, but all of these variations still fall into one of the categories above.
How Sportsbooks Work
In theory and often in practice (not always, but we'll get to that in a minute) a sportsbook will release early lines with low bet limits. As bets come in the sportsbook will shift the line in one direction or the other as necessary to ensure that the money coming in on both teams remains in a balance that minimizes the sportsbook's risk. Because of the vigorish that the sportsbooks charge, they are guaranteed a nice profit if they can eliminate risk and have no interest in the outcome of a game. As more money pours in the lines get sharper and sharper and sportsbooks are able to increase their limits.
Bookmakers make their profit by charging juice/vig. For example if on a moneyline the odds are -250 / +200, the 50 cent gap between is where their profit lies.
Not all sportsbooks always follow the above strategy. Some books will shade lines - either for all players or only for players that they have profiled to be susceptible to this practice - to decrease the return on the bets that the sportsbook thinks will be most popular. For example, if a sportsbook thinks that the Denver Broncos -7 -105 is a fair line, but it also knows that a lot of square players are interested in this game and think the Broncos will win, then the book may shade the line to Broncos -7.5 -115 because they know that the square bettors will still take the Broncos and this will lead to greater expected value for the sportsbook.
The one area where this article lacks is in teaching you how to find an edge. It's not easy and it can't be covered in an article. If you already have one, great. If not, skip to the Find a Tipster with an Edge section.
If you don't currently have an edge but would like to be able to find one, consider starting with Sharp Sports Betting by Stanford Wong. It won't make you a winning tipster in itself, but it'll give you a good lesson in the basics.
Determine if You Have an Edge
If you're not sure whether or not you have an edge, it's more realistic - and indeed far safer - to assume that you do not.
If you do think you have an edge, though, it's best to track your tips for at least a year and to make sure that all of the following are true.
- You beat the closing line on average which says that you are smarter than the market average.
- You have a good Z score and a strong sample size to show that your results likely aren't purely luck.
- You have a high r-squared to show that you are consistently beating the sportsbooks over time, that your bankroll hasn't been subjected to wild swings and that changes in the market are not turning you into a losing tipster.
While I think Pick Monitor to be the best of the web's tip trackers I am obviously biased, so here is a list of well-respected, easy-to-use tracking services for you to consider:
Do you know of another good sports monitor? Tweet @PickMonitor with a link.
Find a Tipster with an Edge
Profitable, consistent tipsters are rare, but they do exist. Pick Monitor has some, BetAdvisor has some, and there are surely others that do as well. Finding your long-term tipster is more about accepting reality than about some hidden formula. The reality is that you can't expect to win more than the -110 equivalent of 56-58% long-term. Moreover, the overwhelming majority of tipsters are long-term losers, so another reality is that seeing a tipster with unbelievable stats through 100 tips probably doesn't mean a whole lot.
Focus on the Right Stats
Win percentage - the most esteemed and beloved stat in the degenerate world - is utterly meaningless aside from playing a role in the expected growth vs expected value debate. A tipster with a proven 70% win rate over a huge sample size isn't worth five cents without knowing more information.
Return on Investment (ROI)
ROI = Profit / Amount Invested
ROI is the staple metric for most tipster-evaluators because it's the only metric that is both widely understood and extremely useful. It quickly tells you how profitable a tipster's average tip is without having to worry about how many tips he makes, what unit system he uses or what kind of odds he plays. It can't be manipulated by playing -1000 favorites.
Beat the Closing Line (BtCL%)
BtCL% can be calculated a few different ways. It can be either the raw number of times you do or don't beat the closing line, or it can be the average amount by which you beat or lose to the closing line. It can be calculated either with regard to the actual closing line or the no-vig closing line. Any way you calculate it - if we're under the assumption that the sports betting market is at least semi-efficient - then a strong BtCL% is a good indicator of who is beating the sportsbooks because of skill versus who is just getting lucky.
Z score is a predictor of future success, though one which is of notably little value at low sample sizes. The higher your absolute Z score, the more likely that your results were gained by skill rather than by luck.
r^2 is the coefficient of determination. Essentially, it tells you how consistent a tipster has been. This is an important factor in determining whether a tipster has achieved his results through luck or through skill, and an even more important factor when determining what kind of bankroll management strategy you can use when following a tipster. Finding a consistent tipster - one who doesn't have many large upswings and downswings - can be just as important as finding a tipster with a strong ROI. This consistency - aside from being easy on your heart - can allow you to bet a higher percentage of your bankroll on each play and thus achieve a stronger return.
Be Mindful of Price
The best, most proven, most consistent tipster in the world is not worth more than your bankroll dictates. Sure, a consistent 58% tipster who tips three -105 lines per day might be worth $10,000/mo to some people, but if you only have a $1,000 bankroll then you can't even dream about spending more than $357/mo for that tipster's tips.
That hypothetical tipster's talent will yield him about 11.9 units each month. If you risk 3% of your bankroll per play that's a profit of $357 with a $1,000 bankroll (actually more if you adjust your bet amount as your bankroll grows, but that's not the point right now). So $357/mo is the upper limit of what you could pay such a tipster, but of course if there's no room for your own profit then there's no point so what you'd actually be willing to pay him is something less than $357.
A Quick Word on Sports Tipping Scams
Sports betting brings with it the theoretical possibility of overnight fortune. Conversely, smart sports betting is far less sexy than the movies or the press will have you think - a slow grind to (relatively) small profits. Tipping scam operations are prolific because degenerates enable them. Sorry to say, but if you're the guy who shells out money to a "tipster" claiming 98% winners then you didn't stand a chance in the first place because you're an emotional, thrill-chasing bettor rather than a disciplined, value-seeking bettor. Serious, rational, level-headed sports bettors don't fall for scams. If you're interested in buying the tips of a tipster, don't suddenly ignore the rules you use to make any other serious purchase. Between Google and your own common sense you should be just fine.
Avoid Unnecessary Emotional Swings
If you are not making your own plays and you're not trying to transition into one day making your own plays then there is no reason for you to watch the games and/or be glued to the scoreboard. Place your bets, leave it alone, and check your bankroll the next day when you go to place your next set of bets. I know it's fun to watch a nail-biter when you have money on the line, but doing so is a very good way to get overly emotional which leaves you trying to ride your hot streak after a big win or chase after a big loss - both ultimately leading to the end of your bankroll.
The only way you will ever be a successful sports bettor is if you treat it like a business rather than a thrill-seeking event. If you can't help but absorb the awesome rush then you should perhaps reconsider what kind of sports bettor you want to be.
Understanding the Profitability of Different Sports
Let's assume - even though it's not true - that closing lines are perfectly efficient. The following table represents - broken down by sport - the average you would win if you risked $100 on the moneyline for every "home" team (the team listed second in Pick Monitor's tracker - which isn't necessarily the home team) at the time of the softest line. Further, since one must be sharp to realize and take advantage of line movements like this, we'll assume that these sharp bettors do not make tips on games where the softest line still comes up shy of the no-vig closer.
Eg, if the Atlanta Braves opened at -115, the line moved as low as -107 and closed at -114 then we assume that you made a $100 tip on the Braves at -107. In this example the Braves are playing the Phillies whose closing line is +106 making the no-vig line for this game (approximately) -110. We're assuming that -110 - which translates to a win percentage of 52.32% - is perfectly efficient - so $100 on this line at -107 gives us an average profit of $1.22
100 * (.5232 * 100/107 - (1 - .5232))
|Sport||Profit per $100 risked||Sample Size|
Data from 9/30/2012 to 2/20/2014.
Where to Bet
Select your Sportsbooks
We'll go over line shopping in more depth a bit later in this article, but know up front that having all of the skill in the world will be meaningless if you don't get good lines and so it's important to have as many sportsbook outs as possible so that you have the greatest chance of getting the best line for each tip. If it's only feasible for you to play with a few different books then it makes the most sense to go with sportsbooks that have different benefits.
Different sportsbooks can be better or worse for different playing styles. Some books are known for their soft "square" lines, others have reduced juice, bonuses, etc.
In general it is recommended to go with the sportsbooks that offer the lowest juice. Bonuses could theoretically offer more value than reduced juice, but such an occasion is rare.
In terms of making sure the sportsbooks you choose will pay you, the advice is as simple as learn how to use Google. Check out sportsbooks the same way you would check out any other big purchase. Look for reviews, complaints, how long they've been in business, if they have a history of paying quickly, etc. Use your common sense to see if the reviews seem genuine or if the reviewer is an affiliate of the sportsbook.
SBR has information on many sportsbooks and is worth a read so long as you are aware of the questionable practices employed by SBR before reading. In essence, that link explains that it's in SBR's best interest financially to trash some sportsbooks and to endorse others.
Maximize Value by Shopping for Lines
When one sportsbook offers a play at -142 while another offers the same play at -128 it's easy to appreciate line shopping, but amature bettors fail to see the big deal when it comes to less severe line gaps. Consequently, because the large majority of line differences are small, many amature bettors forego line shopping altogether.
If you bet $100 per play on 3 plays per day every day for a year while winning 55% of your bets against -110 lines then you would win $5,478.75 that year. If you shopped for -108 lines on all of those plays you would have instead won $6,493.33, an 18.5% increase in earnings for a difference in lines that most people would consider inconsequential. The reality is that 2 cent gaps exist between sportsbooks on almost every play, and sometimes those gaps are much larger. So by not line shopping you are leaving at least 20% of your value on the table.
Luckily line shopping is pretty simple albeit time consuming. You open accounts at as many sportsbooks as possible - or you are willing to walk to as many Las Vegas casinos as possible - and then you just tip the sportsbook that has the most favorable line for each of your plays. The following websites offer invaluable tools to help you find the best lines available.
Do you have an additional line-shopping resource to add? Tweet @PickMonitor with a link.
How Much to Bet
The Kelly Criterion
The Kelly Criterion - even though you probably won't end up using it - is arguably the most important concept for any bettor to understand with regards to managing your bankroll. It explains that betting too much will make you lose everything even if you're the best tipster in the world. Check out this Kelly Criterion Calculator if you don't want to whip out the pencil and paper.
The Kelly Criterion Explained: The General Concept and Its Application In Sports Betting by SBRForum
Kelly tells you the optimal percentage of your bankroll to bet on each play and can be calculated with the formula
K = [P(W) - (1 - W)] / P where W is the implied win rate and P is the payout - the amount you win if the bet is successful.
It's important to note that formula above is for a single independent event. That formula needs to be adjusted if you have multiple bets in pay at the same time. Becuase that adjustment is rather tricky here's another Kelly Criterion Calculater for your enjoyment.
With the Kelly criterion - because you are always betting a fraction of your bankroll rather than a set figure - it is theoretically impossible to ever go bankrupt. However, it is possible for your bankroll to dwindle down so far that your recommended bet size is less than the minimum risk amount at the sportsbooks so it is practically possible to go bankrupt.
Expected Growth versus Expected Value
A lot of sharp and square tipsters alike determine how good a bet is by its expected value. The expected value of a bet is defined as the relative amount that you'd expect to win - on average - if that bet played out infinite times. For example, a bet on -110 odds that has a 55% likelihood of winning has an expected value of 5%.
.55*(100/110) - .45 = .05 Expected value is great if you have an infinite bankroll and have access to infinite bet limits.
But there's a bit of a difficulty here -- namely, expected value ignores any consideration of the relative likelihoods of given outcomes alone. For example a $10,000 bet on a 0.0000000000000000000000000000000000001% likelihood event paying out at +110,000,000,000,000,000,000,000,000,000 ,000,000,000,000 odds corresponds to an expected value of 10% (+$1,000). But who among us would be willing to essentially throw away $10,000 on such a long shot? To put it in perspective you'd be about 1,870 times more likely to win the the New Jersey State Lottery five times in a row, than you would be to win this particular bet. Does it really matter that if by some fluke of nature you actually did win you'd have an unfathomably huge amount of money? If you're like most people, the answer is probably not.
So now here's the difficulty ... there's no way whatsoever to account for this very real phenomenon of preferences by appealing to the theory of expected value alone.
I can't possibly explain the difference between expected value and expected growth any better than Ganchrow did here so I encourage you to read his full explanation when you have a few spare minutes - like right now.
One important thing to take away from this is that - all else equal - given the same EV you'd be better off betting on a favorite than an underdog.
If you can accurately and consistently quantify your edge then it is mathematically correct to vary your bet size based on some variation of the Kelly Criterion. If you can't - and the overwhelming majority of tipsters can't - then flat betting is the only route to go.
Betting a flat 1 - 3% of your bankroll on each tip is a commonly accepted figure. Even though you're not using the Kelly Criterion, though, your bet sizes should still have some mathematical basis.
Sports Betting Money Management by RJ Miller is the best article I've ever read on flat betting. From a purely mathematical standpoint I disagree with some of his points, but they are valuable points nonetheless.
Many see sports betting as a get-rich-quick scheme, but the only way to get rich quick with sports betting is to be extremely careless with your money management strategy.
A largely untalked about key factor for why poor money management is so prevalent - in addition to the obvious culprits of greed, stupidity and addiction - is the relatively small bankrolls that many use. If you own a $220,000 house and a $25,000 car and you make $70,000 per year then putting $1,000 into a sportsbook and trying to responsibly grow it just isn't a reasonable thing to do. Even with a 100% annual ROI it simply won't be worth your time (at least for the first year). So it's understandable how people mismanage their bankroll when they start with a relatively insignificant amount of money and try to win a significant amount of money. That plan usually doesn't work out.
Want me to cover something else? Tweet @PickMonitor with a topic.