Vig (Juice)
The vig (short for vigorish) or juice is the commission sportsbooks charge on bets. It's the house edge—the reason sportsbooks profit regardless of which team wins.
How the Vig Works
The most common vig is embedded in -110 odds on both sides of a spread or total:
- Bet $110 to win $100 on Team A (-110)
- Bet $110 to win $100 on Team B (-110)
If equal money comes in on both sides, the book collects $220 and pays out $210 to the winners. That $10 difference is the vig—a 4.54% cut on every dollar wagered.
Calculating the Vig
To find the vig, convert odds to implied probabilities and see how much they exceed 100%:
| Side | American Odds | Implied Probability |
|---|---|---|
| Team A | -110 | 52.38% |
| Team B | -110 | 52.38% |
| Total | 104.76% |
The 4.76% "overround" is the vig. A perfectly efficient market would sum to 100%.
Vig at Different Odds
The standard -110/-110 isn't universal. Some books offer reduced juice:
| Odds | Vig | Break-even Win Rate |
|---|---|---|
| -110/-110 | 4.54% | 52.38% |
| -108/-108 | 3.77% | 51.92% |
| -105/-105 | 2.44% | 51.22% |
That difference matters. At -105 juice, you need to win 1.16% fewer bets to break even compared to -110. Over thousands of bets, that's significant edge.
Why the Vig Matters for Prediction Markets
On Kalshi and other prediction markets, there's no explicit vig in the traditional sense. You buy contracts at market prices determined by supply and demand.
However, the bid-ask spread functions similarly—you pay a premium to enter and exit positions. Illiquid markets have wider spreads, which creates implicit vig.
This is one reason prediction markets can offer better value than traditional sportsbooks: competition and market structure can compress the effective vig.
Beating the Vig
To profit long-term, your edge must exceed the vig. If you're paying 4.54% vig, you need more than 4.54% expected edge to be profitable.
This is why:
- Line shopping matters. Finding -108 instead of -110 saves real money.
- CLV is the metric. If you're beating the closing line, you're likely overcoming the vig.
- Parlays are dangerous. Each leg multiplies the vig. A 4-leg parlay at -110 has roughly 18% combined vig.
Related Terms
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