Understanding Juice (Vig)
Every bet you make has a built-in cost: the vigorish (vig) or juice. This is how sportsbooks make money—and understanding it is essential to becoming a profitable bettor.
What Is Vig?
When you see a standard market like Over 26.5 (-110) / Under 26.5 (-110), each side has an implied probability of approximately 52.38%.
Let's do the math:
- Total implied probability: 52.38% + 52.38% = 104.76%
- Anything over 100% is the book's edge
- Market vig (or "hold"): 4.76%
Key Insight
The vig is the "tax" you pay on every bet. At -110/-110, you're paying about 4.76% to the sportsbook regardless of whether you win or lose. This is why you need an edge just to break even.
Why Vig Matters Even More in Props
In spreads and totals, the vig is usually standardized at -110. In props, you see much more variation:
| Market Type | Odds | Implied Prob | Total Hold |
|---|---|---|---|
| Standard | -110 / -110 | 52.4% / 52.4% | 4.76% |
| Slightly Juiced | -120 / -105 | 54.5% / 51.2% | 5.7% |
| Heavily Juiced | -140 / +100 | 58.3% / 50.0% | 8.3% |
The Break-Even Win Rate
Each step up in vig raises your breakeven win rate—the percentage of bets you must win just to break even.
Break-Even Win Rate (Negative Odds)
Break-Even % = |Odds| ÷ (|Odds| + 100)=ABS(A2)/(ABS(A2)+100)Break-Even Win Rate (Positive Odds)
Break-Even % = 100 ÷ (Odds + 100)=100/(A2+100)Break-Even Reference Table
Memorize this table—it's your first line of defense against bad bets:
| Odds | Break-Even % | What It Means |
|---|---|---|
| +150 | 40.0% | Win 2 of 5 to break even |
| +110 | 47.6% | Win ~48 of 100 to break even |
| -110 | 52.4% | Win ~53 of 100 to break even |
| -120 | 54.5% | Win ~55 of 100 to break even |
| -130 | 56.5% | Win ~57 of 100 to break even |
| -150 | 60.0% | Win 3 of 5 to break even |
| -170 | 63.0% | Win ~63 of 100 to break even |
| -200 | 66.7% | Win 2 of 3 to break even |
Warning
At -120, you need to win 54.55% of your bets just to break even. At -130, you need nearly 57%. You are not just betting "Will this happen?" You are betting: "Is the true probability higher than the implied probability after vig?"
The Real Question You're Answering
When you place a bet, you're not asking "Will this happen?"
You're asking: "Does this happen more often than the break-even rate?"
Example: Luka Doncic Over 28.5 Points at -150
- Break-even rate: 60%
- You must believe Luka goes over more than 60% of the time
- Not 59%. Not "probably around 60%." More than 60%.
If your honest assessment is 58%, this is a losing bet despite Luka being a great player who often scores 30+.
Vig Comparison: Props vs Main Markets
| Market Type | Typical Vig | Your Disadvantage |
|---|---|---|
| NFL Spread | ~4.5% | Baseline |
| NFL Total | ~4.5% | Baseline |
| Standard Props | ~5-7% | +0.5-2.5% |
| Derivative Props | ~10-15% | +5.5-10.5% |
| One-Way Props | ~20-40% | +15.5-35.5% |
Key Insight
Props offer more edges, but they also come with a higher "tax." The house edge jumps from ~4.5% on main markets to ~7% on standard props, and up to 30%+ on one-way markets. You need a bigger edge to beat the higher vig.
Calculating Your Required Edge
To be profitable, your edge must exceed the vig. Here's how to think about it:
| Your Win Rate | At -110 | At -120 | At -130 |
|---|---|---|---|
| 50% | -4.5% ROI | -8.3% ROI | -11.5% ROI |
| 52% | -0.9% ROI | -4.8% ROI | -8.1% ROI |
| 54% | +2.7% ROI | -1.3% ROI | -4.6% ROI |
| 56% | +6.4% ROI | +2.2% ROI | -1.2% ROI |
| 58% | +10.0% ROI | +5.7% ROI | +2.3% ROI |
Tip
Notice how a 54% win rate is profitable at -110 but losing at -120 and -130. This is why line shopping (finding the best odds) is so critical—it can turn a losing bet into a winning one.
Vig Calculator
Try the interactive calculator for this concept
📝 Exercise
Instructions
Practice calculating implied probability and understanding how vig affects your betting.
Part 1: Calculate Implied Probability
For each prop below, calculate the implied probability of each side and the total market vig.
At -130 odds, what win rate do you need just to break even?
You find a prop at -110 where you believe the true probability is 55%. Is this a good bet?