The vig (or juice) is the sportsbook's built-in fee, baked into the odds. On a standard -110 / -110 line, you must win 52.38% of your bets just to break even, and the book holds about 4.55% of every dollar bet on that market. Over a season, that's real money.
Here's where it comes from, how to strip it out, and what it costs you.
Step 1: Odds are just probabilities
Every American odds number implies a win probability. That's the win rate where the bet breaks even.
- Negative odds (favorite): implied probability = odds / (odds + 100), using the absolute value of the odds.
- Positive odds (underdog): implied probability = 100 / (odds + 100).
| American odds | Implied probability |
|---|---|
| -200 | 66.67% |
| -150 | 60.00% |
| -110 | 52.38% |
| +100 | 50.00% |
| +130 | 43.48% |
| +200 | 33.33% |
At -110: 110 / 210 = 52.38%. That's your break-even win rate.
Step 2: Spot the vig
In a fair market, the probabilities of all outcomes add up to 100%. Sportsbooks price both sides so they add up to more. The extra is called the overround.
A -110 / -110 line:
- 52.38% + 52.38% = 104.76%
- That extra 4.76% is the overround.
The book's actual hold (what it keeps if action is balanced) is a little different: 1 - (1 / 1.0476) ≈ 4.55%. People mix up overround and hold all the time. They're the same margin, measured two ways.
Step 3: Remove the vig (multiplicative method)
To find the "fair" probability of each side, divide each side's implied probability by the total. This is the multiplicative (or proportional) method. It's the most common one.
Fair probability = implied probability / sum of implied probabilities
Example: a game priced at -150 / +130.
- -150 implies 150 / 250 = 60.00%
- +130 implies 100 / 230 = 43.48%
- Total = 103.48%
- Fair favorite = 60.00 / 103.48 = 57.98%
- Fair underdog = 43.48 / 103.48 = 42.02%
Those two now add to 100%. Convert back to odds and you have the no-vig line: about -138 / +138.
One catch: the multiplicative method spreads the margin evenly. Books often shade more margin onto longshots, so other methods (like additive, power, or Shin) can give slightly different fair prices on lopsided markets. For close lines, the multiplicative method works well.
Step 4: What the juice costs you per bet
Say you're a pure coin flipper, a true 50% bettor at -110.
- Win: +0.909 units, 50% of the time
- Lose: -1 unit, 50% of the time
- Expected value = 0.5 x 0.909 - 0.5 x 1 = -0.0455 units per bet
So a break-even-skill bettor loses about 4.55 cents per dollar bet, purely to vig.
Step 5: The season bill
Now scale it up. You bet $100 a game, 500 bets a season, all at -110, and you hit exactly 50%.
| Item | Value |
|---|---|
| Total handle | $50,000 |
| Expected loss per bet | about $4.55 |
| Expected season cost of vig | about $2,273 |
That's $2,273 gone for "breaking even" on your picks. To actually profit, you need to beat 52.38%, not 50%.
The gap between 50% and 52.38% matters a lot. At -110, going 52.38% over 500 bets only gets you to zero. A 54% bettor, which is very good over a large sample, makes roughly 3.1% ROI. Most of what looks like skill is spent paying the vig.
How to pay less juice
- Shop lines. The same game at -105 instead of -110 drops break-even to 51.22%. Over a season that's a big deal.
- Look for reduced-juice books and promos where they are legal for you.
- Compare against no-vig prices. If your bet beats the fair, no-vig line from a sharp market, you likely have value.
- Track closing line value (CLV). Getting better numbers than the close is one of the most reliable signs you are beating the vig long term.
- Watch parlays and props. Margins on these markets are often much higher than on main lines. Run the numbers before you assume a price is fair.
Do the math in seconds
You don't have to do this by hand. EdgeTilt's free calculators include vig removal, an odds converter, a Kelly bet sizer, an arbitrage check, and CLV. Paste in both sides of a line and get the fair price right away. Try them free at edgetilt.com.
FAQ
What is the break-even win rate at -110? 52.38%. You risk 110 to win 100, so 110 / 210 = 52.38%.
How much is the vig on a -110 line? The overround is 4.76% and the book's hold is about 4.55% on a balanced -110 / -110 market.
What is the multiplicative method? Divide each side's implied probability by the total of all sides. The results add to 100% and give fair, no-vig probabilities.
How much does vig cost over a season? For a 50% bettor making 500 bets of $100 at -110, about $2,273 in expected losses.
Is -105 really that much better than -110? Yes. Break-even drops from 52.38% to 51.22%, which is a meaningful chunk of a typical bettor's edge.
This is educational content, not betting advice. 21+. Gamble responsibly. If you or someone you know has a gambling problem, call 1-800-GAMBLER.