Removing the Vig
Every price a book posts has a hidden tax built into it. Learn to peel that tax off and you can finally see what the odds are really saying, and whether a bet is worth making.
What the vig really is
The vig (short for vigorish, also called the juice, the cut, or the hold) is the commission a book charges for taking your bet. It's why a coin-flip game isn't offered at even money. When both sides of a game sit at -110, you're risking $110 to win $100 on something that's basically 50/50. That extra $10 on each side is the vig, and it's how the house pays the bills.
Because the vig is baked right into the odds, the numbers on the screen always make the two outcomes look more likely than they really are. Add up both sides' implied probabilities and you'll get more than 100%. That extra chunk is the book's margin, and peeling it off is how you find the true, fair price.
Turn odds into probabilities
Before you can remove the vig, you turn each price into an implied probability, the win rate the odds are assuming. The formulas are short:
- Minus odds: the number divided by (the number plus 100). So -150 becomes 150 / 250 = 60%.
- Plus odds: 100 divided by (the number plus 100). So +130 becomes 100 / 230 = 43.5%.
Those two add up to 103.5%, not 100%. That extra 3.5 points is the vig. Now we scale it back out.
Removing the vig, step by step
The trick is simple. Divide each side's implied probability by the combined total. That forces the two numbers back to a clean 100% while keeping their relationship to each other intact.
| Side | Posted | Implied | No-vig | Fair odds |
|---|---|---|---|---|
| Team A | -150 | 60.0% | 58.0% | -138 |
| Team B | +130 | 43.5% | 42.0% | +138 |
| Total | 103.5% | 100% |
Team A: 60.0 / 103.5 = 58.0%. Team B: 43.5 / 103.5 = 42.0%. Turn those clean numbers back into American odds and the fair line is about -138 / +138, not the -150 the book is charging. That gap between -150 and -138 is exactly what you're paying for the privilege of betting Team A.
Why this is the most useful math you'll learn
The no-vig price is your baseline for value. Once you can find it, three things open up:
- You can grade any bet. If your read (or a model) says Team A wins 63% of the time but the fair price says 58%, that's a real edge. If your number is below the fair line, pass, no matter how much you like the team.
- You can compare books honestly. A book holding 3.5% is a better deal than one holding 5%, even when the headline odds look about the same. Lower vig means more of your winnings stay yours.
- You can build a fair line off a sharp book. Lots of bettors take the no-vig price from a low-margin book that's known to be efficient, treat it as the true probability, then shop for any other book still offering a better number on that side.
A quick note on three-way markets
Games that can end in a draw (soccer is the big one) have three prices instead of two: home, draw, away. Same method. Turn all three into implied probabilities, add them up, divide each by the total. The only difference is the vig is spread across three outcomes, which makes it a little harder to spot at a glance.
You don't have to do this by hand every time. Plenty of free no-vig calculators do the arithmetic instantly, and it's the same math our own Line Movement tool leans on to track how a market shifts. But knowing why it works is what turns a number on a screen into an actual decision.
Key takeaways
- The vig is the book's built-in commission. It makes the odds imply more than 100% total.
- Turn each side into an implied probability, then divide by the combined total to strip the vig and find the fair price.
- The no-vig price is your value benchmark. Bet only when your estimate beats it.
- Lower-hold books give back more of your winnings, so weigh the margin, not just the headline number.