SPORTS BETTING MATH
INDEPENDENT MATHEMATICAL RESEARCH

Sports Betting
Math

Fair Odds Engine & +EV Calculator Suite

Deconstruct bookmaker margins using advanced probability models, multiplicative overround stripping, and Poisson goal matrices. Identify positive expected value (+EV) and protect bankroll growth with proven mathematical rigor.

Topic illustration: No-Vig Fair Odds Explained: The Mathematics of Bookmaker Margins
9 Calculators •
21 Research Dossiers •
4 Languages •
20+ Formulas •
Site analytics enabled •
Calculations in your browser •
Open Source •
Est. 2026 •
1 Understand the Math
2 Use the Tools
3 Find +EV Edges

PROPORTIONAL MODEL EXAMPLE

How Bookmakers Hide Their Overround

At 1.91 on both outcomes, overround is 4.712042%. Proportional normalization assumes 50% per side, giving fair odds 2.00 and an expected loss of 4.50% per unit wagered. The prices alone do not prove that the true probabilities are 50/50.

Retail Bookmaker Line OR: 4.71%
Side A (Implied: 52.36%) 1.91 (-110)
Side B (Implied: 52.36%) 1.91 (-110)
Sum of inverse prices: 104.71%. Overround 4.71%; proportional expected loss 4.50%.
Multiplicative De-Vig
P_fair = P_implied / 1.0471
Proportional fair odds FAIR: 100.00%
Model probability: side A 2.00 (50.00%)
Model probability: side B 2.00 (50.00%)
A model baseline under proportional margin allocation, not observed true probabilities.
RESEARCH ARCHITECTURE

Research Pillars

Explore the four mathematical disciplines that define quantitative sports analysis, odds de-vigging, and edge quantification.

Topic illustration: No-Vig Fair Odds Explained: The Mathematics of Bookmaker Margins
📐 PILLAR 01 // FAIR ODDS & MARGIN ANALYSIS
PILLAR 1

No-Vig Fair Odds & Bookmaker Overround Decomposition

Mathematical methods for stripping bookmaker margins from odds: Multiplicative, Additive, Power and Shin. Each produces probability estimates under its own margin-allocation assumptions.

Core Formula: P_fair = (1 / O_i) / Σ(1 / O_k)
Topic illustration: Expected Value (+EV) Betting: The Mathematical Path to Profit
📈 PILLAR 02 // EXPECTED VALUE & +EV IDENTIFICATION
PILLAR 2

Expected Value, Overround & Model Assumptions

Formal derivation of EV = (P_win × (Odds - 1)) - (P_loss × 1). Distinguishes quoted overround from model expected loss and explains why the probability estimate determines selection EV.

Core Formula: EV = (P × O) - 1
Topic illustration: Kelly Criterion Staking Guide: The Mathematics of Bankroll Growth
🎯 PILLAR 03 // KELLY CRITERION & BANKROLL OPTIMIZATION
PILLAR 3

Kelly Criterion Staking: Full, Half & Quarter Kelly with Risk of Ruin Analysis

Optimal geometric growth bet sizing derived from Kelly's 1956 paper. Covers fractional Kelly variants, tilt protection, drawdown limits, and risk of ruin simulation.

Core Formula: f* = (b·p - q) / b
Topic illustration: Poisson Goal Expectancy Model: Predictive Football Analytics
⚽ PILLAR 04 // POISSON DISTRIBUTION & MATCH MODELING
PILLAR 4

Poisson Goal Expectancy Engine: 1X2, Over/Under & Correct Score Probabilities

Poisson distribution modeling for football and hockey outcomes. Calculates independent goal probabilities for 1X2, Over/Under 2.5, correct score matrices, and BTTS markets.

Core Formula: P(X=k) = (λ^k · e^-λ) / k!

MATHEMATICAL AXIOMS

Three Models for Evaluating a Bet

✓ 01 // The Vig Tax

Overround and expected loss

At 1.91, break-even probability is 1/1.91≈52.356%. With a50% win probability, each unit has EV=-4.50%. Over 1000 fixed one-unit bets the expected loss is 45 units; the fraction of the starting bankroll depends on its size.

✓ 02 // Kelly Sizing

Log-Wealth Maximization

Kelly maximizes expected log growth for specified probabilities and payouts. Estimation error, finite-horizon losses and operational bankroll limits remain.

✓ 03 // Closing Line Value

A Market Price Benchmark

A no-vig closing line is a model-based benchmark available after the market closes. CLV measures price improvement against it; it does not establish true probability or guarantee profit.

TEST YOUR MATHEMATICAL EDGE

Calculate Your Edge on
Top Sportsbooks

Apply de-vigged fair odds, Poisson goal expectations, and Kelly criterion stakes directly into live betting markets.

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