What is Expected Value (EV)?

Quick Definition

Expected Value (EV) is the average amount you expect to win or lose per bet in the long run. Positive EV (+EV) means the bet is profitable over time. Negative EV (-EV) means you'll lose money in the long run. Understanding EV is the fundamental difference between recreational betting and professional sports betting—it transforms gambling from a game of chance into a mathematical exercise where disciplined bettors gain a measurable edge over the sportsbook.

Formula:

EV = (Win Probability × Profit) - (Loss Probability × Stake)

The key to successful betting isn't winning every bet—it's consistently finding opportunities where your estimated probability of winning exceeds the implied probability offered by the sportsbook's odds. Even professional bettors typically win only 52-58% of their bets, but they profit because they only bet when the math is in their favor.

How It Works: Detailed Sport-by-Sport Examples

NFL Example: Sunday Night Football Spread

Scenario: Buffalo Bills vs Kansas City Chiefs

• Market Line: Bills +3.5 (-110)
• Implied Probability: 52.4% (including vig)
• Your Model's Probability: 58%
• Bet Amount: $110
• If Win: Profit $100
• If Lose: Lose $110

EV Calculation:

EV = (0.58 × $100) - (0.42 × $110)
EV = $58 - $46.20
EV = +$11.80

Per-Bet EV: +$11.80 (10.7% ROI)

Analysis: Your model identifies a 5.6% edge over the market. This is a significant edge in NFL betting where margins are typically razor-thin. Over a full 17-week NFL season with similar edges, betting $110 per game would yield approximately $200 in expected profit.

NBA Example: Total Points Over/Under

Scenario: Lakers vs Nuggets Total

• Market Line: Over 225.5 (-108)
• Implied Probability: 51.9%
• Your Analysis: Pace factors, rest advantage, altitude = 56% Over
• Bet Amount: $108
• If Win: Profit $100
• If Lose: Lose $108

EV Calculation:

EV = (0.56 × $100) - (0.44 × $108)
EV = $56 - $47.52
EV = +$8.48

Per-Bet EV: +$8.48 (7.9% ROI)

Analysis: NBA totals often present value opportunities because they're influenced by multiple variables (pace, back-to-backs, altitude, injuries) that sharp bettors can model more accurately than the general market. The 4.1% edge here represents excellent value in a high-volume market.

MLB Example: Moneyline Underdog

Scenario: Oakland Athletics vs Houston Astros

• Market Line: Athletics +185
• Implied Probability: 35.1%
• Your Model: Pitching matchup, bullpen rest, recent form = 42% Athletics win
• Bet Amount: $100
• If Win: Profit $185
• If Lose: Lose $100

EV Calculation:

EV = (0.42 × $185) - (0.58 × $100)
EV = $77.70 - $58
EV = +$19.70

Per-Bet EV: +$19.70 (19.7% ROI)

Analysis: MLB offers some of the highest EV opportunities in sports betting due to the high variance in baseball and the complexity of properly modeling pitching matchups, bullpen usage, and platoon advantages. A 6.9% edge is substantial and represents the type of opportunity that professional MLB bettors actively seek.

Soccer Example: Premier League Draw

Scenario: Everton vs Southampton

• Market Line: Draw +240
• Implied Probability: 29.4%
• Your Analysis: Defensive styles, historical H2H, motivation = 35% draw probability
• Bet Amount: $100
• If Win: Profit $240
• If Lose: Lose $100

EV Calculation:

EV = (0.35 × $240) - (0.65 × $100)
EV = $84 - $65
EV = +$19.00

Per-Bet EV: +$19.00 (19% ROI)

Analysis: Soccer draws are frequently undervalued by casual bettors who prefer backing a winner. This creates opportunities when two defensively-solid teams with similar quality face each other. The 5.6% probability edge translates to significant long-term value.

Expected Value Comparison Table

Bet Type	Win Probability	Odds	Implied Probability	Edge	$100 Bet EV	ROI
NFL Spread (Sharp)	55%	-110	52.4%	+2.6%	+$4.55	4.1%
NBA Total (Value)	58%	-105	51.2%	+6.8%	+$12.38	11.8%
MLB Underdog	42%	+165	37.7%	+4.3%	+$11.30	11.3%
Soccer Draw	35%	+240	29.4%	+5.6%	+$19.00	19%
Parlay (2-leg)	30%	+260	27.8%	+2.2%	+$2.00	2%
Public Favorite	68%	-300	75%	-7%	-$9.33	-3.1%
Player Prop (Edge)	60%	-115	53.5%	+6.5%	+$8.70	7.6%

Table Insights: Notice how higher odds don't necessarily mean better EV—what matters is the gap between your win probability and the market's implied probability. The public favorite shows negative EV despite a 68% win rate because the odds don't compensate for the risk. Player props and niche markets often offer the best EV opportunities due to less efficient pricing.

When to Use vs Not Use Expected Value

✅ Best Situations to Apply EV Betting

Situation 1: You Have a Proven Edge
When you've tracked 200+ bets and consistently beat closing lines or show positive CLV (Closing Line Value), you have statistical evidence of an edge. This is when EV betting becomes your primary strategy. Example: A bettor who specializes in Big Ten college basketball and has beaten closing lines 58% of the time over two seasons should aggressively bet any game where their model shows +EV.

Situation 2: High-Volume, Lower-Variance Markets
NFL spreads and totals, NBA games, and soccer matches provide enough volume to let EV materialize over a season. With 1,000+ games per season in major leagues, the law of large numbers works in your favor. A 3% edge over 500 bets at $100 each yields $1,500 in expected profit.

Situation 3: You Can Line Shop Effectively
When you have accounts at 5+ sportsbooks and can consistently find the best number, you're adding 1-2% to your EV on every bet. Getting -105 instead of -110 on a bet you'd make anyway is pure profit over time.

Situation 4: Niche Markets with Information Edges
Lower leagues, player props, or markets where you have specialized knowledge (injury reports, weather impacts, coaching tendencies) create the largest EV opportunities. A bettor who follows minor league baseball closely might find 10-15% edges regularly.

❌ Situations to Avoid EV-Only Thinking

Situation 1: Insufficient Bankroll for Variance
If you have a $500 bankroll and bet $100 per game, even with +EV bets, you'll likely go broke during a normal losing streak before EV can materialize. EV betting requires proper bankroll management—typically 1-2% of bankroll per bet maximum.

Situation 2: Can't Accurately Estimate Probabilities
If you're new to a sport or don't have a model/system for estimating win probabilities, your EV calculations are meaningless. A recreational bettor who "feels like" a team has a 60% chance to win is likely overconfident. Without calibrated probability estimates, you're just guessing.

Situation 3: Entertainment/Recreational Betting
If you're betting to make games more exciting and $50 won't impact your life, strict EV betting removes the fun. It's okay to make -EV bets for entertainment if you budget for it like any other entertainment expense. Just don't confuse it with profitable betting.

Situation 4: Futures and Low-Volume Props
Betting a team to win the championship in Week 1 might show +EV based on your model, but with only one outcome and months of uncertainty, variance overwhelms expected value. You need volume for EV to manifest.

Common Expected Value Mistakes

❌ Mistake 1: Confusing EV with Outcome

Wrong Approach: "I made five +EV bets and went 1-4, so EV doesn't work."

Right Approach: Track 200-500 bets before evaluating EV accuracy. Variance means you'll have losing weeks and months even with an edge.

Why It Matters: A bettor with a genuine 5% edge will still lose money 40% of the time over 100-bet samples. If you abandon +EV betting after short-term losses, you'll never realize long-term profits. Example: A bettor with +5% EV betting $100 per game has a 35% chance of being down money after 100 bets, but a 95% chance of profiting after 1,000 bets.

❌ Mistake 2: Overestimating Your Win Probability

Wrong Approach: "I've watched this team all season—I'm 90% sure they cover" (reality: 65%)

Right Approach: Calibrate your estimates by tracking predicted vs actual outcomes. Be conservative and honest about uncertainty.

Why It Matters: Overestimating by just 10% can turn a -EV bet into a perceived +EV bet. Example: You estimate 70% win probability on -200 odds (66.7% implied). You calculate +$3.33 EV on a $100 bet. Reality: Your true win rate is 60%, making it -$13.33 EV. Over 100 bets, this 10% overestimation costs you $1,666 in expected value.

❌ Mistake 3: Not Accounting for Vig/Juice in Profit Calculation

Wrong Approach: Using stake instead of profit: (0.55 × $100) - (0.45 × $100) = +$10

Right Approach: At -110 odds: (0.55 × $90.91) - (0.45 × $100) = +$5.00

Why It Matters: Ignoring vig makes every bet look better than it is. The wrong calculation above shows +10% EV when the true EV is +5%. Over a year of betting, this error makes you think you have double the edge you actually have, leading to overbetting and bankroll problems. On 500 bets at $100 each, this miscalculation represents a $2,500 difference in expected profit.

❌ Mistake 4: Chasing High EV Without Considering Sample Size

Wrong Approach: Betting obscure Uzbekistan soccer because your model shows 25% EV on one match.

Right Approach: Focus on markets with enough volume to validate your edge and enough liquidity to get bets down.

Why It Matters: A single 25% EV bet is still just one bet—you could easily lose and never get another opportunity to bet that market. Meanwhile, a 3% edge on NFL games gives you 250+ opportunities per season. Example: Bettor A makes 10 bets at 20% EV and goes 3-7 (down $340). Bettor B makes 200 bets at 4% EV and goes 106-94 (up $824). Lower EV with volume beats high EV without it.

❌ Mistake 5: Ignoring Bankroll Management in EV Betting

Wrong Approach: "This is +15% EV, so I'll bet 30% of my bankroll!"

Right Approach: Use Kelly Criterion or fractional Kelly (typically 0.25-0.5 Kelly) to size bets based on both EV and variance.

Why It Matters: Even with an edge, overbetting leads to ruin. The Kelly Criterion for a 55% win probability at -110 odds suggests betting just 4.5% of bankroll. Betting 30% on this same edge gives you a 40% chance of losing half your bankroll before doubling it, even though you have an advantage. Example: $5,000 bankroll, +10% EV bet. Kelly says bet $227. Betting $1,500 instead creates a 28% risk of ruin despite the edge.

❌ Mistake 6: Failing to Account for Closing Line Value

Wrong Approach: Calculating EV based on opening lines without tracking where lines close.

Right Approach: Track CLV (Closing Line Value) as the ultimate test of whether your bets are truly +EV.

Why It Matters: The closing line is the sharpest number—it incorporates all information and sharp money. If you consistently bet worse than closing lines, your EV calculations are wrong regardless of short-term results. Example: You bet Chiefs -3 (-110) and the line closes at -4.5. You gave up 1.5 points of value. Studies show bettors who beat closing lines by even 1-2 points are profitable long-term, while those who don't beat closing lines lose regardless of their perceived edge.

Strategic Implementation Guide: 7-Step EV Betting System

Step 1: Build Your Probability Model

Action: Create a systematic way to estimate win probabilities—power ratings, statistical models, or hybrid approaches combining quantitative data with qualitative factors.

Tools Needed: Historical data (5+ years), Excel/Python for modeling, regression analysis for key factors.

Expected Outcome: After 100 tracked bets, you should see if your model has predictive power. If your 60% estimates win 58-62% of the time, your calibration is good.

Step 2: Establish Multiple Sportsbook Accounts

Action: Open accounts at 5-8 different sportsbooks to maximize line shopping opportunities.

Tools Needed: Odds comparison sites (Oddschecker, OddsJam), bankroll spread across books.

Expected Outcome: Line shopping adds 1-2% to your effective EV. On a $50,000 annual betting volume, this equals $500-$1,000 in additional profit.

Step 3: Set Minimum EV Thresholds

Action: Only bet when your calculated EV exceeds +3% (for high-volume markets) or +8% (for lower-volume markets).

Tools Needed: Spreadsheet or betting app that calculates EV automatically.

Expected Outcome: This filter eliminates marginal bets where small errors in probability estimation would make bets -EV. Reduces bet volume by 60-70% but concentrates on highest-quality opportunities.

Step 4: Implement Proper Bet Sizing

Action: Use fractional Kelly Criterion (0.25-0.5 Kelly) based on your edge and confidence level.

Tools Needed: Kelly calculator, disciplined bankroll tracking.

Expected Outcome: Optimal growth with managed risk. A bettor with 5% average edge and $10,000 bankroll betting quarter-Kelly should expect 15-20% annual bankroll growth with <5% risk of 30% drawdown.

Step 5: Track Every Bet and Calculate Actual EV

Action: Log every bet with: date, sport, bet type, odds, estimated probability, actual outcome, closing line.

Tools Needed: Spreadsheet or dedicated tracking software (mybets.gg, Pikkit, or custom Excel).

Expected Outcome: After 200 bets, you'll have statistical evidence of whether your edge is real. Compare your CLV—if you're consistently beating closing lines by 1+ point/cent, you have a genuine edge.

Step 6: Review and Recalibrate Monthly

Action: Each month, analyze which bet types, sports, or situations produced the best actual vs expected results.

Tools Needed: Statistical analysis of your tracked bets, broken down by category.

Expected Outcome: Identify your strongest edges. You might discover you're +8% EV on NBA totals but -2% on NFL spreads, allowing you to specialize and improve overall performance.

Step 7: Scale Gradually as Edge is Proven

Action: Only increase bet sizes after 500+ bet sample confirms your edge. Increase bankroll allocation to sports/markets where you've demonstrated consistent CLV.

Tools Needed: Confidence intervals, statistical significance testing.

Expected Outcome: Sustainable growth without overexposure. A proven bettor might start with $50 bets, scale to $100 after 500 bets showing +4% ROI, then to $200 after another 500 bets maintaining the edge.

Real-World Historical Example: NFL Season EV Tracking

Scenario: Professional bettor specializing in NFL totals over the 2023 season, betting exclusively when model showed +5% EV or better. Starting bankroll: $25,000. Bet sizing: 2% of current bankroll per bet (half-Kelly for conservative growth).

Season Performance Breakdown

Month	Bets Placed	Record	Win Rate	Avg EV	Monthly P/L	Bankroll	ROI
September	18	10-8	55.6%	+6.2%	+$612	$25,612	6.8%
October	32	15-17	46.9%	+5.8%	-$892	$24,720	-5.4%
November	35	21-14	60.0%	+7.1%	+$2,145	$26,865	12.3%
December	38	20-18	52.6%	+5.5%	+$721	$27,586	4.0%
January (Playoffs)	11	7-4	63.6%	+8.3%	+$1,038	$28,624	18.8%
Season Total	134	73-61	54.5%	+6.3%	+$3,624	$28,624	14.5%

Key Takeaways from This Example

Variance is Real: Despite maintaining a +5.8% average EV in October, the bettor lost money that month with a 46.9% win rate. This is normal variance—even with an edge, you'll have losing months. The bettor stayed disciplined and continued betting their system.

EV Materialized Over Volume: With 134 bets, the actual ROI (14.5%) exceeded the average calculated EV (6.3%). This outperformance is within normal variance and validates the model's predictive power. The 54.5% win rate at average odds of -110 produces approximately 8% ROI, with additional value from line shopping.

Bankroll Management Protected Capital: By betting 2% of current bankroll, the bettor's largest bet was never more than $572 (2% of peak bankroll). During the October losing streak, bet sizes automatically decreased, preserving capital for the profitable months ahead.

Closing Line Value Confirmed Edge: The bettor tracked CLV and beat closing lines on 58% of bets by an average of 0.8 points. This independent validation confirms the model identifies value before the market corrects.

Specialization Paid Off: By focusing exclusively on NFL totals rather than spreading across all bet types, the bettor developed deep expertise in pace factors, weather impacts, and coaching tendencies that created consistent edges.

Platform Integration: How MyBets.gg Tracks Expected Value

Automated EV Calculation: MyBets.gg automatically calculates expected value for every bet you log by comparing your entered odds against closing lines and market consensus. The platform tracks your estimated win probability (if you choose to enter it) and compares it against actual outcomes to measure calibration accuracy over time.

Closing Line Value Dashboard: The platform displays your CLV for every bet and aggregates it by sport, bet type, and time period. You'll see exactly which markets you're beating and by how much—the most reliable indicator of long-term profitability. Visual graphs show your CLV trend over time, helping you identify when your edge is improving or deteriorating.

EV Tracking Features:

• Real-Time EV Calculator: Enter any odds and your estimated win probability to instantly see expected value and recommended bet size using Kelly Criterion
• Historical EV vs Actual Results: Compare your predicted EV against actual outcomes to validate your model's accuracy
• Sport-Specific EV Breakdown: Identify which sports and bet types produce your highest EV to focus your betting
• Line Shopping Optimizer: Track which sportsbooks consistently offer the best odds for your preferred bet types
• Probability Calibration Charts: See if your 60% estimates actually win 60% of the time—essential for accurate EV calculation

Screenshot Description: The MyBets.gg EV Dashboard displays a clean interface with your lifetime EV metrics at the top: Total Bets (347), Average EV (+4.2%), Expected Profit ($1,834), Actual Profit ($2,156). Below, a line graph shows monthly EV vs actual results, demonstrating how variance smooths out over time. The bottom section breaks down EV by sport, showing NBA totals at +6.8% EV across 89 bets as your strongest market, while NFL spreads show only +1.2% EV across 67 bets, suggesting you should reduce volume there.

Value Proposition: Most bettors lose because they don't know if they have an edge. MyBets.gg removes the guesswork by providing objective, data-driven analysis of your betting performance. By tracking EV and CLV automatically, you'll know within 100 bets whether your approach is profitable or needs adjustment—saving you thousands in potential losses. The platform transforms betting from subjective guessing into quantifiable skill development, showing you exactly where you have edges and where you're burning money.

Conclusion: Making Expected Value Your Competitive Advantage

Expected value is the fundamental concept that separates winning bettors from losers. While recreational bettors chase wins and losses emotionally, professional bettors focus exclusively on finding positive EV opportunities and letting mathematics work over volume. Every bet you place should answer one question: "Is this +EV?" If you can't calculate or estimate the expected value, you shouldn't be betting.

The path to profitable betting isn't complicated, but it requires discipline:

1. Develop a method to estimate true probabilities more accurately than the market (statistical models, situational analysis, or specialized knowledge)
2. Compare your probabilities to available odds to identify positive expected value
3. Bet only when you have an edge and size bets proportionally to your advantage
4. Track closing line value to validate your edge independent of short-term results
5. Accept variance and maintain discipline through inevitable losing streaks
6. Continuously refine your process based on data, not emotions

Remember that even a small edge compounds dramatically over time. A bettor with just 3% EV who places 500 bets per year at $100 average stake will earn $15,000 annually—not from luck, but from systematic exploitation of market inefficiencies. Scale that to $500 per bet, and you're generating $75,000 per year from the same skill edge.

The bettors who succeed long-term aren't the ones with the biggest bankrolls or the most insider information—they're the ones who understand expected value, track it religiously, and have the discipline to bet only when the math is in their favor. Start calculating EV on every bet today, and you'll immediately separate yourself from 95% of bettors who are gambling blindly.

Use tools like MyBets.gg to track your expected value versus actual results, identify your strongest markets, and build a data-driven betting approach that generates consistent profits. The edge is out there—you just need the discipline to find it and the patience to let it materialize over time.