Let’s start with a confession. The numbers on your sportsbook screen are not what they seem. They’re probability dressed up, with a hidden fee inside. This fee is the vig, the house’s profit margin.
Think of it like the Matrix. You’re seeing a comfortable reality designed to keep you calm. The sum of all implied probabilities in a market always goes over 100%. That’s the overround, the sportsbook’s clever accounting.
This article is your red pill. We’re going to remove the vig and explain the tricky terms—American, Decimal, Fractional. You’ll learn to see the naked truth behind the numbers.
What’s the real chance of an event, without the bookmaker’s tax? That’s the zero vig fair line. It’s the fair price, the pure signal in the noise. Consider this your financial self-defense class.
Ready to see how the machine really works?
Odds formats quick conversions and pitfalls rounding and precision
To calculate an edge, you need to speak the betting language. There are three main dialects: American, decimal, and fractional. Misunderstanding them can cost you a lot.
Each format shows your possible return. But they use different ways to say it. Learning to quickly switch between them is key to avoiding mistakes.
American: The Egoist’s Ledger
American odds use a $100 benchmark. It’s a system that’s as odd as it is common. It’s all about what you risk to win a Benjamin, or what a C-note can earn for you.
See a negative number like -150? That’s the price for a favorite. It tells you how much to risk to win $100. You bet $150 to profit $100.
A positive number, like +200, is for the underdog. It shows the profit from a $100 risk. A $100 bet profits $200. Simple, right? The ego comes in when you realize the entire system revolves around a single, round, American dollar figure.
The pitfall? Mental math. Converting +235 or -175 to an implied probability on the fly is where rounding errors sneak in and chip away at your perceived value.
Decimal: The Pragmatist’s Choice
Welcome to the betting world’s Esperanto. Popular across Europe, Canada, and Australia, the decimal format is beautifully logical. The number you see is your total return per unit staked.
A price of 2.50 means for every $1 you bet, you get $2.50 back if you win. Your profit is included. Just multiply your stake by the decimal figure. Done.
Its clarity is its superpower. Comparing value between 1.85 and 1.90 is instantaneous. The common mistake? Forgetting that this number already includes your original stake, unlike other formats. This is a critical detail when you’re learning how to convert odds between systems.
Fractional: The Traditionalist’s Quirk
Fractional odds are the stubborn grandparent of the betting family. Prevalent in UK and Irish horse racing, they refuse to use the metric system. A price of 5/1 (spoken “five-to-one”) means you profit £5 for every £1 wagered.
Your stake is not included in the quoted figure. A winning £10 bet at 5/1 returns £60 (£50 profit + £10 stake).
The quirk? They can look intimidating. Is 10/11 a good price? (It’s a heavy favorite). The conversion requires an extra mental step. The pitfall is double: mis-calculating the total return and dealing with rounding when fractions get weird (e.g., 6/4 simplifies to 3/2, but not all books display it that way).
| Format | Region | Key Rule | Payout Formula (Stake = $100) | Biggest Quirk |
|---|---|---|---|---|
| American (Moneyline) | United States | Based on $100 standard. Negative for favorites, positive for underdogs. | +250: Win $250 profit. -150: Risk $150 to win $100 profit. | The egoist’s benchmark. All calculations mentally tie back to $100. |
| Decimal | Europe, Canada, Australia | Number represents total return (stake + profit) per unit. | 2.50: $100 stake returns $250 total ($150 profit). | The pragmatist’s dream. Clean, includes stake, easy comparisons. |
| Fractional | UK, Ireland (Horse Racing) | Ratio shows profit-to-stake. Stake is not included in the quote. | 5/1: $100 stake profits $500, returns $600 total. | The traditionalist’s puzzle. Requires extra step to calculate total return. |
So, why does this matter? Precision. A misread decimal as a fractional price, or a rounding error on a long moneyline, can turn a positive EV bet into a loser. Your “edge” can vanish into the spreadsheet cells before the game even starts.
The first step to fair pricing is seeing the true price. And that means fluency in all three dialects.
From odds to implied probability and back calculators and formulas
Understanding implied probability is key to grasping the bookmaker’s message. It’s like a secret code that turns a price into a clear chance. Think of it as a special tool you should have found in your cereal box.
Knowing how to convert odds to implied probability is essential. It’s what sets the analytical player apart from the hopeful punter. It’s the difference between feeling lucky and knowing the price.
The Universal Translator: Implied Probability
Every odds set, like -150 or +200, tells a story. It’s the bookmaker’s guess of an event’s chance, with a bit extra for their profit (the vig).
Turning odds into a percentage is more than math—it’s a revelation. Seeing +200 as a 33.3% chance or -150 as a 60% chance changes everything. You’re no longer reading poetry; you’re reading the balance sheet.
The formulas are simple. Just remember them, or bookmark this handy odds converter calculator for easy use.
| Odds Format | Example | Implied Probability Formula |
|---|---|---|
| American (+) | +250 | IP = 100 / (Odds + 100) |
| American (-) | -120 | IP = |Odds| / (|Odds| + 100) |
| Decimal | 3.00 | IP = 1 / Odds |
| Fractional | 5/1 | IP = Denominator / (Numerator + Denominator) |
Why bother with this? Because adding up the implied probabilities for all outcomes in a market will always exceed 100%. That extra is the book’s profit, or “hold.” Spotting it is your first step toward beating it.
Reversing the Engine: From Probability to Odds
Now for the real magic. What if you have a better guess of a team’s chance? To find value, you need to turn your belief into a fair price. This is algebra, but I promise not to make your eyes glaze over.
You just flip the formulas. If you believe a team has a true 25% chance to win, what’s the fair American odds?
- Start with the probability as a decimal: 0.25.
- Fair Decimal Odds = 1 / 0.25 = 4.00.
- That converts to fair American odds of +300.
If the sportsbook is giving +250, you have a reason to be wary. Their price implies a 28.6% chance. If your 25% estimate is sharper, the book’s line is not good value.
This reverse engineering is your key to finding an edge. It turns a gut feeling into a quantifiable bet. Or, more often, it talks you out of a bad one.
Removing overround for two way and multi way markets proportional vs equal margin methods
We now understand implied probability. But, we find a market lie: the total of all outcomes is more than 100%. This isn’t a math mistake. It’s the vig, the bookmaker’s profit margin.
In a two-way market, if both sides have a 52.38% implied probability, the total is 104.76%. That extra 4.76% is the house’s edge. Your goal is to remove this to find the truth.
Finding the Zero-Vig Line
The zero-vig line, or fair price, is the ultimate goal. It shows what odds would be in a market without profit. This is what you compare your own assessment to find value.
For example, if a book lists a moneyline with a total implied probability of 105%, the 5% overround is the vig. Removing it shows the true probabilities the market implies, before the taxman took his cut.
Proportional Method: The Democratic Tax
This method works like a progressive tax system. The overround is removed from each outcome in proportion to its size. The bigger the implied probability, the more of the vig it was carrying.
The formula is: Fair Probability = (Outcome Implied Probability) / (Total Market Implied Probability).
For a -110 vs -110 game (each IP = 52.38%, total = 104.76%):
Fair Probability = 52.38% / 104.76% = 49.94% for each side.
The fair odds for a 49.94% probability are roughly +100.2. See the table below.
| Outcome | American Odds | Implied Probability | Fair Probability (Proportional) |
|---|---|---|---|
| Team A | -110 | 52.38% | 49.94% |
| Team B | -110 | 52.38% | 49.94% |
| Market Total | 104.76% | 100.00% | |
Equal Margin Method: The Flat Tax
The equal method assumes the bookmaker added the same fixed margin to each outcome’s true probability. It’s a flat tax. Every outcome pays the same fee.
The calculation is different: Fair Probability = Outcome Implied Probability – (Overround / Number of Outcomes).
Using the same -110 example (Overround = 4.76%, 2 outcomes):
Fair Probability = 52.38% – (4.76% / 2) = 52.38% – 2.38% = 50.00% exactly.
In this simple two-way case, it yields a clean 50/50 fair line, or +100 odds.
So, which method reveals the real zero vig fair line? It’s a delightful mystery. Some books price proportionally, others closer to equal. For multi-way markets (like a horse race with 10 runners), the difference can be significant. The proportional method is often considered more accurate for real-world bookmaking.
Mastering this removal is your first step in seeing the board clearly. It transforms you from a price-taker to a price-analyst. Now you know what the game really costs.
Break even tables for common prices bookmark for live use
Book this page now. This section is your reality check, formatted for speed. It turns odds into win-rate requirements. It’s the cold splash of water after the hype of a “lock” pick.
You don’t just need to be right; you need to be right at a specific frequency to overcome the bookmaker’s built-in tax. This section is your reality check, formatted for speed.
The Bettor’s Cheat Sheet
Think of this as the nutritional label on your betting slip. While the odds tell you the payout, the break even percentage shows the required win rate. It’s the difference between seeing a -110 line as a “coin flip” and understanding it’s a 52.4% uphill climb.
This knowledge is power. It instantly reveals why constantly betting heavy favorites is a financial slow bleed. And why finding mispriced underdogs is the holy grail.
Below is your essential reference table. Memorize the key ones, or better yet, keep this open in a tab while you shop lines. It translates the language of odds into the stark mathematics of survival.
| American Odds | Implied Probability | Break Even Percentage | The Reality Check |
|---|---|---|---|
| -500 | 83.3% | 83.3% | You must be nearly certain. A “sure thing” isn’t sure enough. |
| -200 | 66.7% | 66.7% | Win two out of every three bets. Consistently. Good luck. |
| -110 | 52.4% | 52.4% | The standard juice. You need to win more than 52 out of 100. |
| +100 (Even) | 50.0% | 50.0% | A true coin flip. The vig is your only enemy here. |
| +200 | 33.3% | 33.3% | Win one in three times to break even. This is where value hides. |
| +300 | 25.0% | 25.0% | Only need to be right a quarter of the time. Suddenly, longshots look different. |
| +500 | 16.7% | 16.7% | A 1-in-6 shot. The required break even percentage is low, but the win rate is steep. |
See the pattern? For negative odds, the required win rate is daunting. For positive odds, the threshold is lower, but the events are less likely. The magic happens when your assessed probability of an event is higher than the break-even percentage the odds demand. That’s your edge.
Let’s get brutally pragmatic. If you’re blindly betting -200 favorites, you’re signing up for a 66.7% success rate marathon. The sports landscape is rarely that predictable.
Conversely, a +300 underdog only needs to win 25% of the time to justify the bet. This table flips the script. It forces you to ask: “Do I believe this will happen more often than the break-even math requires?” If not, you’re donating.
Use this map live. Before you click “place bet,” cross-reference the price with the required win rate. It’s the quickest gut-check in the business. It turns intuition into a calculated decision. This cheat sheet doesn’t guarantee wins, but it absolutely prevents one thing: betting without understanding the true cost of entry.
Price sensitivity and expected value delta from line move examples
Forget crystal balls. The real magic in betting lies in finding the right moment for a line move. Expected Value (EV) is key, but it’s all about the price being right, not just your prediction.
A small change in the line, like from -110 to -105, is huge. It drops the break-even rate by over 1%. This tiny change can turn a hobby into a business.
This is price sensitivity. It shows how much your profit changes with each odds change. It’s not just about math; it’s about finding value.
The Calculus of Edge
Let’s define our terms. Your edge is your probability minus the market’s implied probability. The formula is simple: Edge = (Your Probability – Implied Probability) * 100%.
If you think Team Alpha has a 55% chance to win, and the fair line is 50%, you have a +5% edge. But, the wrong price can make your edge disappear.
Line moves show the market’s mood. A shift from -3 to -3.5 is more than a number. It could be sharp money or new information. Your job is to understand and act fast.
Imagine an NFL game with a point spread of +2.5 (-110). You think the underdog has a 55% chance to cover. The implied probability at -110 is 52.38%. Your edge is 2.62%.
Through line shopping, you find +3.0 (-110). This half-point change is huge for covering a spread. Your model’s true probability of covering jumps to 58%.
The implied probability at -110 is 52.38%. Your new edge is 5.62%. You’ve doubled your expected value by finding a better number. This is the power of sensitivity.
Let’s see how small price changes can make a big difference. The table below shows how aggressive odds shopping can change profitability.
| Scenario | Odds Found | Implied Probability | Your Assessed Prob. | Edge (%) | EV on $100 Bet |
|---|---|---|---|---|---|
| Baseline (Tight Market) | -110 | 52.38% | 55.0% | +2.62 | +$2.38 |
| Better Price (Line Shopping) | -105 | 51.22% | 55.0% | +3.78 | +$3.44 |
| Key Number Move (e.g., +2.5 to +3.0) | -110 (on +3.0) | 52.38% | 58.0% | +5.62 | +$5.11 |
| Reaction to Sharp Money | +100 (was +90) | 50.00% | 53.5% | +3.50 | +$3.50 |
| Poor Price (Lazy Betting) | -115 | 53.49% | 55.0% | +1.51 | +$1.37 |
The third row is the hero. It shows finding a better point can be the most lucrative move. The last row is a warning. Paying too much vigorish can ruin your edge.
This isn’t just number-crunching. It’s the calculus of edge. It needs a trusted model and discipline to act only when the market rewards you. The delta from a line move is your paycheck. Make sure you’re the one cashing it.
Line shopping tactics books limits boosts and withdrawal friction
In sports betting, having only one sportsbook is a disadvantage. Line shopping isn’t advice; it’s a commandment. Think of your betting money as a stock portfolio. You wouldn’t use just one broker, right? You’d look for the best price.
Source 3 suggests having accounts at multiple books. Odds differ because of risk and action levels. This difference is your chance. Getting sign-up bonuses is just the start. The real challenge is comparing live odds across sites every time.
The Art of the Deal (With Algorithms)
This isn’t about refreshing browser tabs manually. It’s about using systems. Watch the opening line and its changes across 5-6 books. Sharp books like Pinnacle or Betfair often lead. Softer books like FanDuel or Caesars might be slower.
Your advantage is spotting these delays. It’s like digital arbitrage. You’re betting against the market’s inefficiency. Use tools and alerts for odds comparison. Make your line shopping automatic.
Limits: The Silent Killer of Value
Here’s a harsh truth. A book might offer a great +105 vs. the market’s +100. You bet big, win, then face $5 stakes. What’s the point? Your edge is blocked by limits.
Limits help books manage risk from winning players. They’re the fine print that can ruin your feast. Always check a book’s limit policy. Sometimes, taking a slightly worse price is smarter.
Withdrawal Friction: The Hidden Tax
Withdrawal friction, like fees and delays, erodes your capital. You might earn a 5% ROI, but lose 2% to fees and another chunk to waiting. This is the hidden tax on profits.
This tax can make some strategies unprofitable. Always consider withdrawal costs and speed. A book with great odds but bad banking is a trap.
Understanding trade-offs is key. Do you want the best price or ease and reliability? The answer varies based on your bankroll and strategy.
| Sportsbook | Odds Quality (Sharpness) | Typical Sign-Up Boost | Limit Tolerance | Withdrawal Friction (Fee/Speed) |
|---|---|---|---|---|
| DraftKings | Soft to Medium | $1,000 Bonus | Low – Quick to limit | Low fee / 1-3 days |
| FanDuel | Soft | $1,000 Risk-Free Bet | Medium | No fee / 24-48 hrs |
| BetMGM | Medium | $1,500 Bonus | Medium | $5 fee / 3-5 days |
| Caesars Sportsbook | Soft | $1,250 Bet Credit | High | No fee / 2-4 days |
| Pinnacle | Very Sharp | None | Very High | Low fee / |
Your mission is clear. Build a network of accounts. Use sharp books for signals and soft books for value bets. Always check for limits and withdrawal issues. True line shopping is a holistic strategy, not just price-checking. It’s about negotiating with algorithms and understanding the fine print.
Market microstructure hold percentage parlay pricing same game correlations
Let’s explore the hidden world of sports betting. You know how to change American decimal fractional odds and find implied probability. Now, learn how casinos use these numbers to make money.
This isn’t about luck. It’s a system made for profit. Knowing this is key to being a smart bettor.
How the Sausage is Made
Every betting market has a profit margin for the book, called the “hold” or “overround.” It’s like a service fee you pay before betting. It’s the difference between 100% and the sum of the implied probabilities for all outcomes in a market.
For a simple -110/-110 point spread, the implied probability for each side is about 52.38%. Adding them together gives 104.76%. The extra 4.76% is the hold. It’s the book’s expected profit on total money wagered, assuming balanced action.
The hold percentage varies by market. Liquid, efficient markets like NFL spreads have low holds. Exotic props and parlays? That’s where the meat grinder really spins.
| Bet Type | Typical Odds Format | Sum of Implied Probabilities | Approximate Hold % |
|---|---|---|---|
| NFL Point Spread | -110 / -110 | 104.76% | 4.76% |
| Moneyline (Close Fight) | +150 / -180 | ~108.50% | 8.50% |
| 3-Way Moneyline (Soccer) | +200 / +220 / +150 | ~107.25% | 7.25% |
| Player Prop (Over/Under) | -115 / -115 | ~105.88% | 5.88% |
Parlays: The Book’s Favorite Lottery Ticket
Parlays are a clever marketing trick. They promise big wins from small bets. But mathematically, they’re bad for players.
Books don’t just add the hold from each leg. They multiply it. When you combine two -110 bets, you might think you’re getting fair odds. You’re not. The book multiplies the implied probability (with vig included) for each leg, creating a compounded edge that grows exponentially with each added bet.
Let’s say you parlay two NFL spreads at -110 each. The true odds of hitting both are about 3-to-1 (+300). A “fair” payout would be +300. But a typical book pays +264. That missing 36 cents on the dollar? That’s the parlay hold working overtime.
- 2-Leg Parlay: Fair Odds: +300 | Typical Payout: +264 | Extra Hold: ~10%
- 4-Leg Parlay: Fair Odds: +1500 | Typical Payout: +1228 | Extra Hold: ~15%+
It’s a terrible deal. The book’s risk management is simple: they love unbalanced action on parlays because the math is so heavily in their favor.
Same-Game Correlations: The Hidden Trap
This is where it gets really clever. Some outcomes within a game are logically connected. Betting a quarterback to throw over 300 yards and his team to win seems like a smart, correlated play.
You’d think parlaying these should give you an edge, as one bet boosts the chance of the other. The book’s algorithms are way ahead of you. They adjust the parlay odds to account for this correlation, effectively removing the “free” value.
For example, a QB’s over 300 yards and a team win might have a true correlation that increases the combined probability to 40%, not the 35% you’d get by multiplying independent probabilities. Sharp books will price the parlay based on the 40% probability, not the 35%. Your perceived edge vanishes.
The lesson? The market’s microstructure—from the broad hold percentage to the specific pricing of parlays and correlated plays—is a finely tuned profit engine. Your job is to see the cogs and gears, so you can avoid being the fuel.
Practical worksheet build a converter plus EV and CLV helper
This section is your workshop, where theory meets action. Knowing odds and probability is powerful. But it’s even more useful if you can use it quickly. We’re making your tool.
This isn’t about coding. It’s about using a spreadsheet to manage your bets. This tool does the math so you can focus on why you’re betting.
Your Personal Betting Swiss Army Knife
Our worksheet has four main functions. Think of them as different tools in one.
First, it changes any odds format to any other. American, Decimal, Fractional—just input one, get them all. No more switching between websites or doing math in your head.
Second, it shows the implied probability from any odds. See a price, know the bookmaker’s real chance.
Third, it removes the vig. It uses our methods to find the zero vig fair line. This shows the market’s true opinion, without the book’s profit.
Fourth, it calculates your edge. Input your true probability, and it shows your Expected Value (EV). Remember, positive EV is key. For a refresher on EV basics, check out our guide on EV basics.
Lastly, it tracks your Closing Line Value (CLV). Did you bet at +150 before it moved to +130? That positive CLV shows you beat the market.
Doing this manually is slow. Automation is your advantage. Set up the formulas once, and your analysis time per bet drops to seconds.
Here’s a blueprint for your worksheet columns. Copy this structure.
| Function | Input Cell | Formula / Logic | Output |
|---|---|---|---|
| Odds Conversion | American Odds (e.g., +150) | =IF(A2>0, (A2/100)+1, (100/ABS(A2))+1) for Decimal | Decimal, Fractional, Implied % |
| Implied Probability | Decimal Odds | =1/B2 | Bookmaker’s Implied % |
| Zero-Vig Fair Probability | Implied % for All Outcomes | =C2/SUM($C$2:$C$N) for each outcome | True Market Probability |
| Expected Value (EV) | Your Fair Odds & Bet Odds | =(Your Fair Prob * Possible Win) – (1-Your Fair Prob)*Stake | EV in $ and % |
| Closing Line Value (CLV) | Your Odds Taken, Closing Odds | =Your Implied % – Closing Implied % | CLV Percentage Points |
To build it, follow these steps:
- Create a new sheet with labeled columns: “Bet Description”, “American Odds”, “Decimal Odds”, “Implied %”, “Fair % (Zero-Vig)”, “My Fair %”, “EV”, “Closing Odds”, “CLV”.
- In the “Decimal Odds” column, use the conversion formula from the American odds input.
- In the “Implied %” column, use =1/[Decimal Odds Cell].
- For a two-way market, calculate the zero vig fair line in the “Fair %” column. If Team A’s implied % is in cell D2 and Team B’s is in D3, use =D2/(D2+D3) for Team A’s fair probability.
- The “EV” column is where you shine. Input your assessed true probability. The formula is: (Your Probability * Possible Profit) – ((1 – Your Probability) * Stake). A positive number is green light territory.
- Your break even percentage is simply 1 divided by your decimal odds. Knowing this instantly tells you how often you need to be right.
This worksheet transforms you. You stop guessing about value. You have a single source of truth that shows your edge—or lack thereof—in stark numbers. It turns betting from a game of gut feelings into a process of analytical execution.
Compliance and record keeping logging books timestamps and screenshots
Record-keeping is like the foundation of a skyscraper. It’s the part that keeps everything stable, even if it’s not glamorous. It’s like doing taxes in April, not exciting but necessary.
This discipline is key to being a proactive analyst, not just a gambler. You’ve learned to convert, calculate, and shop for lines. Now, it’s time to keep a detailed log.
The Unsexy Foundation of Success
Why is this so important? Our memories can be deceiving. They tend to remember wins and justify losses. A log acts as an impartial witness, like a bodycam for your bankroll.
This isn’t about looking back. It’s about creating a data set for analysis. Was that streak skill or luck? Which sportsbook gives you the best prices? Your log has the answers.
Your Betting Audit Trail
Every bet is a piece of data. To use it, you need a consistent format. Think of it as a detective’s file for each bet.
Your log should have the who, what, when, and why. Here’s what you need for each entry:
- Bookmaker: Which shop took your action?
- Timestamp: Date and exact time of placement.
- Sport & Market: NFL Moneyline, NBA Player Prop, etc.
- Bet Type & Odds: Stake, odds format (American, Decimal), and the price.
- Your Rationale/Edge: The most important column. Why did you bet? “Line was +150, my model had it at +120” or “Arbitrage opportunity with Book Y.”
And here’s the pro move: screenshot your betslip. Every single time. This is your proof. Books can have “glitches.” Your screenshot doesn’t.
To visualize it, here’s how a single entry in your betting ledger should be structured:
| Field | Example Entry | Primary Purpose |
|---|---|---|
| Timestamp | 2023-11-05, 19:45 EST | Sequencing & time-based analysis |
| Bookmaker | Bookmaker A | Track value by shop for line shopping |
| Sport/Market | NFL – Game Total Over/Under | Categorize performance |
| Odds & Stake | American: -110, Stake: $100 | Calculate ROI & bet sizing |
| Your Rationale | “Public heavy on Over, sharp money on Under. My model projected 42 points, line was 45.” | Post-mortem analysis on edge identification |
This system serves two masters, one scarier than the other.
First, the tax man. The IRS wants you to report gambling wins. A detailed log with timestamps and screenshots is your defense during an audit. It turns a chaotic pile of transactions into a clean, professional record.
Second, and more importantly, your future self. After a month or a season, you can sort this log. Filter all bets from “Bookmaker B.” Are you profitable there? Filter by “NFL Player Props.” Is your edge real or imagined?
This audit trail turns intuition into intelligence. It shows you where your actual value is found, guiding future line shopping and model refinement. It’s the unsexy, non-negotiable bedrock of a sustainable strategy.
Quiz and exercises ten conversions and real ticket examples with solutions
Knowledge not tested is knowledge forgotten. Think of this as your last pop quiz, without the stress. Let’s see if you can spot the vig and smell the edge.
Final Exam: Do You Get It?
Convert +235 to Decimal and Fractional odds. Decimal is 3.35. Fractional is 47/20. What’s the implied probability of 1.85 Decimal odds? It’s 54.05%. Given two sides at -110, what’s the book’s hold? The answer is 4.55%.
Now, a real ticket. You bet $100 on an NFL game at +105. The fair price, after removing vig, was +108. Was it a +EV play? The break even percentage for +105 is 48.78%. Your estimated true probability was higher. That’s a positive expected value move.
Another. A futures market lists a team at +800. Convert those American decimal fractional odds. Decimal is 9.00. The implied probability is 11.11%. If your model says their true chance is 14%, you have a clear edge.
From Theory to Ticket
This is where reading pretty numbers stops and thinking like a sage begins. The math is just the start. The real skill is applying it to the ticket in your hand, knowing your break-even point, and understanding the market’s microstructure. Go forth and calculate.