Value Bet Calculator
Calculate expected value (EV) and identify profitable betting opportunities. Find out if bookmaker odds offer value and get Kelly Criterion stake recommendations.
Your True Win Probability
Your assessment of the actual win probability
%
The decimal odds offered by the bookmaker
How much you plan to bet
Your total betting bankroll (for Kelly Criterion stake recommendation)
Click an example to see how Expected Value (EV) identifies profitable betting opportunities. Notice how true probability vs bookmaker odds determines long-term profitability!
Profitable Opportunity
• True Probability: 65%
• Bookmaker Odds: 2.20
• £20 Stake
• +£8.60 EV (43% edge)
Fair Odds (Break-even)
• True Probability: 45.45%
• Bookmaker Odds: 2.20
• £20 Stake
• £0.00 EV (0% edge)
Losing Bet (Avoid)
• True Probability: 30%
• Bookmaker Odds: 2.00
• £20 Stake
• -£8.00 EV (-40% edge)
Expected Value (EV): The average profit/loss you can expect from a bet over the long term
Value Percentage: Your edge over the bookmaker (positive = profitable long-term)
Fair Odds: What the odds should be based on your probability assessment
Kelly Criterion: Mathematical formula for optimal bet sizing to maximize bankroll growth
What is Value Betting?
Value betting is the fundamental strategy used by professional bettors to achieve long-term profitability. A value bet exists when the odds offered by a bookmaker are greater than the true probability of that outcome occurring.
Unlike casual bettors who focus solely on picking winners, professional bettors ask: "Are the odds offering value?" Even a favorite might represent poor value if the odds are too short, while an underdog might offer excellent value if the odds are generous relative to their actual chances.
Example: If you assess a team has a 60% chance to win, but the bookmaker's odds imply only a 50% probability, that's a value bet. You won't win every time (60% means you lose 40% of the time), but over many similar bets, you'll make a profit.
How to Calculate Expected Value
Expected Value (EV) is the cornerstone of value betting. It tells you the average profit or loss you can expect from a bet over the long term.
The EV Formula
EV = (True Probability × Decimal Odds) - 1
Or alternatively: EV = (Probability × Profit) - ((1 - Probability) × Stake)
Step-by-Step Example
Let's calculate the EV for Liverpool to beat Brentford:
- Your probability estimate: 75% (0.75)
- Bookmaker odds: 1.40
- Your stake: £20
Calculation: EV = (0.75 × 1.40) - 1 = 1.05 - 1 = 0.05
This gives us +0.05 or +5% Expected Value. This means over many similar bets, you expect to make 5% profit per £1 wagered.
Interpretation: Over 100 bets at £20 each (£2,000 total), you'd expect to make £100 profit (5% of £2,000). This is excellent value.
Understanding Your Results
Expected Value (EV)
The average profit/loss per bet over the long term. Positive EV = profitable, Negative EV = losing proposition.
Value Percentage
Your edge over the bookmaker. +5% value means you have a 5% advantage. Target 3%+ for good value bets.
Fair Odds
What the odds should be based on your probability assessment. If fair odds are higher than bookmaker odds, value exists.
Implied Probability
The bookmaker's assessment of the outcome's likelihood (1/decimal odds × 100). Value exists when your probability exceeds this.
Kelly Criterion
Mathematical formula for optimal bet sizing. We recommend Quarter Kelly (25% of full Kelly) to reduce volatility while still capitalizing on your edge.
How to Assess True Probability
Accurate probability assessment is critical for value betting success. Here are the main methods:
1. Statistical Models
Use historical data including win/loss records, home/away splits, goals scored/conceded, recent form, and head-to-head records to build probability models.
2. Form Analysis
Analyze last 5-10 matches, goal trends, clean sheet frequency, and performance against similar opposition to assess current team strength.
3. Situational Factors
Consider motivation (league position, cup importance), rest days, travel distance, manager tactics, and home advantage statistics.
4. Team News
Key injuries, suspensions, manager changes, and squad rotation significantly impact win probability. Stay updated on team news.
5. Use Multiple Sources
Combine expert predictions, statistical databases, our Mr Super Tips predictions, and market consensus to refine your assessments.
Long-Term Value Betting Strategy
Success with value betting requires discipline, patience, and proper bankroll management:
Key Principles
- Think in hundreds of bets, not individual results
- Use Kelly Criterion or fixed percentage (1-3%) for stake sizing
- Only bet when you have significant edge (3%+ EV)
- Track all bets to evaluate your probability accuracy
- Accept short-term variance - losing streaks are normal
- Never chase losses by increasing stake sizes
- Line shop across multiple bookmakers for best odds
For a comprehensive guide on value betting strategies, read our Value Betting Explained guide.
Frequently Asked Questions
What is expected value in betting?
Expected value (EV) is the average profit or loss you can expect from a bet over the long term. It's calculated using the formula: EV = (True Win Probability × Decimal Odds) - 1. A positive EV means the bet is profitable long-term, while negative EV means it's a losing proposition.
How do you calculate expected value for a bet?
To calculate expected value: 1) Assess the true win probability (your estimate), 2) Compare it to the bookmaker's odds, 3) Use the formula: EV = (Probability × Decimal Odds) - 1, or alternatively: EV = (Probability × Profit) - ((1 - Probability) × Stake). Our calculator does this automatically for you.
What is a positive value bet?
A positive value bet exists when the bookmaker's odds underestimate the true probability of an outcome. For example, if you believe a team has a 60% chance to win but the bookmaker's odds imply only 50%, that's a value bet. Over many bets with positive value, you will make a profit.
Can you make money from value betting?
Yes, value betting is the only sustainable way to profit from sports betting long-term. Professional bettors consistently find positive expected value opportunities and use proper bankroll management. However, you need accurate probability assessments, discipline, and enough bankroll to survive short-term variance.
What is the Kelly Criterion?
The Kelly Criterion is a mathematical formula for optimal bet sizing that maximizes long-term bankroll growth. Formula: (bp - q) / b, where b = decimal odds - 1, p = win probability, q = loss probability. Most professionals use fractional Kelly (25-50% of full Kelly) to reduce volatility.
How accurate do my probability estimates need to be?
The more accurate your probability estimates, the more profitable your value betting will be. Even small errors compound over time. Professional bettors aim for probabilities within 2-5% of true values. Track your estimates against actual results to calibrate your assessments and improve accuracy.
Should I bet on every positive value opportunity?
No, focus on bets with significant edge (3%+ EV) and matches you've researched thoroughly. Marginal value bets (1-2% EV) may not overcome estimation errors. Quality over quantity - bet selectively on opportunities where you have high confidence in your probability assessment.
How do bookmaker margins affect value?
Bookmaker margins (overround) reduce potential value. A typical 5% margin means the sum of implied probabilities is 105% instead of 100%. Lower-margin bookmakers like Pinnacle offer better value opportunities. Comparing odds across bookmakers helps find the best prices and maximize value.
What is the difference between expected value and implied probability?
Implied probability is what the bookmaker's odds suggest about the likelihood of an outcome (calculated as 1/decimal odds × 100). Expected value compares YOUR probability assessment to the bookmaker's odds to determine if a bet is profitable. Value exists when your assessment exceeds the implied probability.
How long does it take to see results from value betting?
You need at least 100-200 bets to evaluate performance meaningfully. Short-term variance is high - you might win or lose over small samples regardless of bet quality. Over 500-1,000 bets, positive EV strategies will show profitability if your probability estimates are accurate. Think long-term, not individual results.