Vigorish

What is Vigorish?

You bet $110 to win$100 on the Chiefs. Your friend bets $110 to win$100 on the Eagles (opposite outcome). One of you wins $100, the other loses$110.

The math: Combined you put in $220, combined you take back$210 ($110 stake +$100 win). The bookmaker keeps $10 risk-free.

That $10 is the vigorish - the hidden tax on every bet you make.

In plain English: Vigorish (vig) is how bookmakers guarantee profit regardless of who wins. It's built into the odds, making every bet slightly unfair in the house's favor.

TL;DR - Quick Reference

Bottom line: Every bet includes a hidden fee. Understanding vig is the first step to profitable betting.

For Beginners: The Bookmaker Tax

Think of vigorish as a sales tax on betting. When you buy something for $10 with 10$11. With betting, the "tax" is hidden inside the odds.

The Fair Coin Flip Example

Fair odds (no vig):

• Heads: 2.00 decimal odds (50% probability)
• Tails: 2.00 decimal odds (50% probability)
• Total implied probability: 50% + 50% = 100% (fair)

Bookmaker odds (with vig):

• Heads: 1.91 decimal odds (52.4% implied probability)
• Tails: 1.91 decimal odds (52.4% implied probability)
• Total implied probability: 52.4% + 52.4% = 104.8%

That extra 4.8% is the vig. The bookmaker priced both outcomes as if they're more likely than 50%, guaranteeing profit. This is known as overround.

Why "110 to Win 100"?

American odds of -110 are standard vig for spread betting:

• You risk $110 to win$100
• If you win: Get back $210 ($110 stake + $100 profit)
• If you lose: Lose $110
• The extra $10 you risk is the vig

To break even at -110 odds: $Breakeven = \frac{110}{110 + 100} = \frac{110}{210} = 52.38\%$

You need 52.4% win rate just to break even, not 50%. That 2.4% difference is the vig eating your profits.

The Math Behind Vig

Calculating Vig from Decimal Odds

Formula:$Vig = \left(\frac{1}{Odds_A} + \frac{1}{Odds_B}\right) - 1$

Example: Tennis match Djokovic vs. Alcaraz

• Djokovic: 1.85
• Alcaraz: 2.10

$Vig = \left(\frac{1}{1.85} + \frac{1}{2.10}\right) - 1 = (0.541 + 0.476) - 1 = 0.017 = 1.7\%$

Implied probabilities:

• Djokovic: 1/1.85 = 54.1%
• Alcaraz: 1/2.10 = 47.6%
• Total: 101.7%

The probabilities add up to more than 100% because the bookmaker built in 1.7% profit margin.

Converting Vig to Fair Odds

To find the fair odds (no vig), remove the overround:

Fair Probability = Implied Probability / (1 + Vig)

Using the tennis example:

• Djokovic fair probability: 54.1% / 1.017 = 53.2%
• Alcaraz fair probability: 47.6% / 1.017 = 46.8%
• Now adds to 100% ✓

Fair odds:

• Djokovic: 1/0.532 = 1.88 (was 1.85)
• Alcaraz: 1/0.468 = 2.14 (was 2.10)

The bookmaker shaved about 0.03-0.04 odds from each side. That's the vig.

Vig Across Different Markets

Why Vig Varies

Lower vig markets:

• High betting volume (NFL, NBA)
• Sharp bettor participation
• Competitive bookmaker landscape
• Main markets (moneyline, spread)

Higher vig markets:

• Low liquidity (niche sports)
• Recreational bettor focus
• Many possible outcomes
• Exotic bets (props, parlays)

How Vig Destroys Your ROI

Even a "small" vig has massive long-term impact.

Example: 1000 Bets at -110 Odds

Scenario: You're a skilled bettor with 55% win rate (excellent!)

At fair odds (no vig):

• 550 wins × $100 profit =$55,000
• 450 losses × $100 loss = -$45,000
• Net profit: $10,000
• ROI: +10%

At -110 odds (4.5% vig):

• 550 wins × $100 profit =$55,000
• 450 losses × $110 loss = -$49,500
• Net profit: $5,500
• ROI: +5%

The vig cut your profit in HALF - from $10,000 to$5,500.

The Breakeven Trap

Without vig, you need 50% win rate to break even. With standard -110 vig:

$Breakeven = 52.38\%$

What this means:

• 51% win rate at -110 = LOSING MONEY
• 52% win rate at -110 = LOSING MONEY
• 53% win rate at -110 = Barely profitable (0.6% ROI)

You need to be 4.8% better than a coin flip just to break even. That's hard.

Vig in Parlays: The Silent Killer

Parlays are vig death traps because vig compounds with each leg.

Two-Leg Parlay Example

Individual bets:

• Game 1: -110 (4.5% vig)
• Game 2: -110 (4.5% vig)

Combined parlay:

• Fair odds: 4.00 (two 50-50 events)
• Actual odds: ~3.64
• Total vig: ~9.5% (not 4.5%!)

The vig doubles! Every added leg multiplies the bookmaker's edge.

5-leg parlay at -110 per leg:

• Individual vig: 4.5% per leg
• Combined vig: ~20-25%

This is why parlays feel exciting but rarely win long-term. The vig compounds exponentially.

Beating the Vig: Strategies

You cannot eliminate vig (it's built into odds), but you can minimize its impact:

1. Line Shopping

Compare odds across 5+ bookmakers. Line shopping is essential for minimizing vig impact.

Example: NFL Chiefs -3

• Bookmaker A: -110
• Bookmaker B: -108
• Bookmaker C: -105
• Savings: 5¢ = ~2% better ROI

Over 1000 bets at $100, that 2$2,000 extra profit**.

Use the Odds Converter to quickly compare.

2. Avoid High-Vig Markets

Stick to low-vig markets: ✅ NFL/NBA spreads (4-5% vig) ✅ Major tennis matches (3-5% vig) ✅ Soccer main markets (6-8% vig)

Avoid high-vig traps: ❌ Horse racing (15-20% vig) ❌ Parlays (10-25% vig) ❌ Prop bets (10-25% vig) ❌ Live betting (8-15% vig)

3. Use Betting Exchanges

Exchanges vs. Bookmakers:

Exchanges (Betfair, etc.) charge 2% commission on net winnings vs. 5-10% bookmaker vig. That's 50-80% less cost.

Downside: Lower limits for winning players, less liquidity in niche markets.

4. Focus on Value, Not Wins

The vig rule: You must find bets where true probability significantly exceeds implied probability.

Example:

• Bookmaker odds: 2.00 (50% implied probability with vig removed = ~48% true implied)
• Your calculated true probability: 55%
• Edge: 55% - 48% = 7% (worth betting!)

Use the Value Bet Calculator to identify +EV opportunities.

5. Arbitrage (Risk-Free)

Arbitrage exploits vig differences across bookmakers to guarantee profit.

Example:

• Bookmaker A: Team A at 2.10
• Bookmaker B: Team B at 2.10
• Combined implied: 47.6% + 47.6% = 95.2% (under 100%!)

Bet both sides, profit regardless of outcome.

Use the Arbitrage Calculator to find opportunities.

Vig vs. Margin vs. House Edge

These terms are often used interchangeably, but have subtle differences:

They all mean the same thing: The built-in cost that ensures the house profits long-term.

Use the Margin Calculator to calculate vig/margin for any set of odds.

Related Concepts

• Margin: Another name for vig, common in European betting. Margin and vig are identical concepts.
• Implied Probability: The probability suggested by odds. Vig inflates implied probabilities above true probabilities.
• Expected Value (EV): Vig reduces EV of every bet. A break-even bet at fair odds becomes negative EV with vig.
• Value Betting: To beat the vig, you must find odds where true probability > implied probability by enough to overcome vig.
• Odds: Vig is built into all odds. Use Odds Converter to compare different formats.

Practical Tools

Calculators for Vig Analysis

1. Margin Calculator - Calculate exact vig from any set of odds
2. Odds Converter - Compare odds across formats and remove vig
3. Implied Probability - See true vs. implied probability
4. Value Bet Calculator - Find bets with edge > vig
5. Arbitrage Calculator - Exploit vig differences for guaranteed profit

Key Takeaways

• ✅ Vig is inevitable - Every bet includes bookmaker commission (3-25% depending on market)
• ✅ Breakeven increases - At -110 odds, you need 52.4% win rate (not 50%) to break even
• ✅ ROI gets cut - Vig can reduce your profit by 50%+ compared to fair odds
• ✅ Parlays compound vig - Multi-leg parlays have 10-25% total vig
• ✅ Line shop always - Finding better odds = free money
• ✅ Focus on low-vig markets - NFL spreads (4.5%) better than props (25%)

Remember: The vig is a tax on every bet. Minimize it through line shopping, exchanges, and smart market selection. Ignore it at your financial peril.

FAQ

What's a typical vig percentage?

It varies by market:

• Best: Tennis, NFL spreads (3-5% vig)
• Average: Soccer, NBA (5-8% vig)
• Worst: Horse racing, parlays, props (15-25% vig)

Rule of thumb: If odds are -110/-110, vig is ~4.5%. If you see -115/-115 or worse, vig is 6%+.

Use the Margin Calculator to check exact vig for any odds.

How does vig affect my breakeven win rate?

Formula:$Breakeven = \frac{Risk}{Risk + Win}$

Examples:

• -110 odds: 110/(110+100) = 52.4% breakeven
• -120 odds: 120/(120+100) = 54.5% breakeven
• +100 odds: 100/(100+100) = 50% breakeven (fair odds)

The higher the vig, the higher your required win rate.

Is vig the same as house edge?

Similar concept, different contexts:

• Vig: Sports betting term for bookmaker's margin
• House Edge: Casino term for mathematical advantage

Both mean: The built-in cost that ensures the house profits.

Key difference: Casino house edge is fixed (e.g., roulette is always 2.7%). Betting vig varies by market (3-25%).

Can I avoid vig completely?

No, but you can minimize it:

1. Use betting exchanges - 2% commission vs. 5-10% bookmaker vig
2. Line shop - Save 1-3% by finding best odds
3. Stick to low-vig markets - NFL spreads (4.5%) vs. parlays (20%)
4. Arbitrage - Exploit vig differences for guaranteed profit

Reality: Even professionals pay 2-5% vig. The key is finding +EV bets where edge > vig.

Why is parlay vig so high?

Vig compounds with each leg.

Example: 3-leg parlay at -110 per leg

• Leg 1 vig: 4.5%
• Leg 2 vig: 4.5%
• Leg 3 vig: 4.5%
• Total vig: ~13-15% (not 4.5%!)

The math: Each leg's vig multiplies. Two -110 bets individually have 4.5% vig each, but combined parlay has ~9% vig.

Avoid parlays unless you enjoy recreational betting. The vig makes them -EV long-term.

How do I calculate vig from American odds?

For two-outcome markets (spread, moneyline):

1. Convert both sides to decimal:
   • -110 → 1.909
   • -110 → 1.909
2. Calculate implied probabilities:
   • 1/1.909 = 52.4%
   • 1/1.909 = 52.4%
3. Add them:
   • 52.4% + 52.4% = 104.8%
4. Vig = Total - 100%:
   • Vig = 4.8%

Shortcut: If both sides are -110, vig is always ~4.5%.

Use the Margin Calculator to do this instantly.

Final Word: Understanding vig is the foundation of profitable betting. Every successful bettor knows: it's not about winning bets, it's about finding bets where your edge exceeds the vig. Master this, and you're ahead of 95% of recreational bettors.