You have a profitable strategy, but you are currently down 20 units. Is your edge gone, or is this just Variance?
In sports betting, a positive Expected Value (EV) does not guarantee short-term profits. “Variance” measures the volatility of your results—how far your actual winnings can deviate from your expected winnings. Our Sports Betting Variance Calculator uses statistical analysis (Standard Deviation and Monte Carlo simulations) to show you the “Cone of Uncertainty.” It calculates the probability of being in a downswing and estimates the maximum drawdown you should expect over a specific number of bets.
Betting Variance Calculator
Risk AnalysisHow to Use the Calculator
This tool allows you to stress-test your betting strategy against the reality of mathematics. Here is how to configure your simulation:
- Enter Your Stats:
- Flat Stake ($): Your standard bet size.
- Avg Decimal Odds: The average price you take (e.g., 2.00 for even money, 3.50 for underdogs).
- Win Rate (%): Your actual or estimated strike rate. Note: If your Win Rate × Odds is less than 100%, you have negative EV and will lose long-term.
- Set Sample Size (N): Enter the number of bets to simulate (e.g., 1,000 for a season). Variance is always higher over smaller samples.
- Analyze the Risk Metrics:
- Standard Deviation (SD): This number represents the “swing.” 68% of your results will fall within ±1 SD of your EV.
- Probability of Loss: The likelihood that, despite having a good strategy, you will still lose money over this specific number of bets.
- Estimated Max Drawdown: The average “worst-case scenario” dip in your bankroll during the simulation.
Real-World Examples: The “Safe” vs. “Value” Approach
Variance hits different strategies differently. High odds strategies require much larger bankrolls to survive downswings.
Example 1: The Even-Money Bettor (Low Variance)
Scenario: You bet spreads (Odds 1.91) with a 55% Win Rate over 500 bets.
- The Result: The calculator shows a Probability of Loss of ~2%. Your expected Max Drawdown might be around 15-20 units.
- Takeaway: This is a stable strategy. If you are down 50 units, something is likely wrong with your handicapping, not just variance.
Example 2: The Value Bettor (High Variance)
Scenario: You bet on Horse Racing or Underdogs (Odds 4.00) with a 28% Win Rate (Great edge!).
- The Result: Over 500 bets, your Probability of Loss is nearly 15%, despite your edge. Your Max Drawdown could easily exceed 50+ units.
- Takeaway: A 50-unit loss here is “normal noise.” Without this calculator, you might panic and abandon a winning strategy, not realizing that high-odds betting requires a massive bankroll to absorb the swings.
Frequently Asked Questions (FAQ)
What is Standard Deviation (SD) in betting?
Standard Deviation measures how spread out your betting results are from the average (Expected Value). A low SD means your bankroll grows steadily. A high SD means your graph looks like a rollercoaster. In sports betting, higher odds always result in higher Standard Deviation.
What is a “Drawdown”?
A drawdown is the decline in your bankroll from its peak to its lowest point before it recovers. For example, if you go from $1,000 to $1,200, then drop to $800, your drawdown is $400 (from the $1,200 peak). This calculator estimates the average maximum drawdown you will face.
How many bets do I need to confirm my edge?
It depends on the odds, but generally, you need a sample size where the “Probability of Loss” drops below 1-5%. For low odds (2.00), 500-1,000 bets are often enough. For high odds (4.00+), you may need several thousand bets to prove that your results aren’t just luck.