Three words for two ideas
Juice and vig are the same thing. Both mean the margin a book puts into its prices so that, over enough bets, it comes out ahead whoever wins. The full word, vigorish, is older than any sportsbook software.
Hold is a separate idea. The vig is what the prices promise. The hold is what the book really keeps once the games are over and the week is graded. The two numbers are related, and they are almost never the same.
The general case is covered in how bookies make money. This note deals with the arithmetic: how to put a number on the margin of any line you offer.
Turn the price into a probability
Every American price implies a probability, meaning the chance of winning at which the bet would break even.
For a negative price, divide the price by the price plus 100. A -110 line works out to 110 ÷ 210, which is 52.38%.
For a positive price, divide 100 by the price plus 100. A +130 line works out to 100 ÷ 230, which is 43.48%.
The minus sign is dropped in both cases. The only thing the sign tells you is which formula to use.
Add the two sides together
A fair line with no margin would have implied probabilities that add up to exactly 100%. A real line always adds up to more, and the vig lives in that extra amount.
Take the most common line in the business, -110 on both sides. Each side works out to 52.38%, so together they come to 104.76%. The 4.76 points over 100 are called the overround. Action Network's explainer calculates juice exactly this way, by adding the two implied probabilities and subtracting 100.
This is the quickest way to compare two lines. The bigger the total, the more the prices favor the book.
Why a book keeps 4.55%, not 4.76%
The overround is a good measure for comparing prices. It is not the share of the money that stays with the book.
Suppose two players each bet $220 on the same game at -110, one on each side. The book takes in $440. The winner gets back their $220 plus $200 in winnings. The loser's $220 stays with the book. So the book pays out $420 and keeps $20.
$20 out of $440 is 4.55%.
The general formula is one minus one divided by the total of the implied probabilities. With -110 on both sides, that is 1 − 1 ÷ 1.0476, which comes to 4.55%. That is what the book keeps on each dollar wagered when the money is perfectly balanced.
The same arithmetic on other lines
| Line | Implied probabilities | Overround | Margin on balanced money | |---|---|---:|---:| | -110 / -110 | 52.38% + 52.38% | 4.76% | 4.55% | | -105 / -105 | 51.22% + 51.22% | 2.44% | 2.38% | | -115 / -105 | 53.49% + 51.22% | 4.71% | 4.50% | | -120 / +100 | 54.55% + 50.00% | 4.55% | 4.35% | | -150 / +130 | 60.00% + 43.48% | 3.48% | 3.36% |
Two rows are worth a closer look. Reduced juice at -105 cuts the margin almost in half, which is why a book offering it needs to know what it is giving away. And the moneyline with a clear favorite carries less margin than the standard spread, even though its prices look more lopsided.
Parlays multiply the margin
Each leg of a parlay brings its own margin, and the margins multiply.
A two-team parlay at -110 per leg pays about +264. If each leg were a true coin flip, the fair payout would be +300. On that assumption the book's edge is about 8.9% on two legs, 13.0% on three and 17.0% on four.
That is the main reason parlays matter so much to a book's results. It is also why a player who parlays everything is paying a much bigger margin than they realize.
Hold: what is left when the week ends
Three terms turn the theory into accounting.
- Handle is the total amount wagered.
- Win is what the book keeps after paying out winning bets.
- Hold is the win divided by the handle.
Nevada's regulated sportsbooks held 7.75% of everything wagered over the twelve months to 30 June 2026, according to the Gaming Control Board's monthly report. That is above the 4.55% a straight -110 line promises. Part of the gap comes from parlays, props and futures carrying bigger margins than a straight spread.
Hold can also land well below the theory. The margin only shows up as calculated when the money is balanced. When most of a book's players end up on the same side and that side wins, the week can finish in the red on a line that was priced perfectly.
One week, worked through
Take a small book with $40,000 of handle in a week, all of it on -110 lines.
- On perfectly balanced money: the margin is 4.55%, about $1,820.
- If the same book ran reduced juice at -105: the margin falls to 2.38%, about $952.
- In a real week: neither figure is what actually arrives. Players lean toward favorites and popular teams, so some games are lopsided. If those favorites cover, the book gives back the margin it collected on the balanced games.
This is why player limits exist. A limit stops one player, or one crowded side, from wiping out a week of margin.
The hold also comes before costs. The platform comes off the top. On a per-head plan that is $8 or $11 per active player per week, depending on the tier. What the bill is made of goes through that side in detail.
Using the numbers
On a pay per head platform the prices arrive already set. That is part of what the platform is for: the lines come in priced, so nobody on your side has to set them by hand.
The arithmetic still matters, for three reasons:
- It tells you which markets carry the most margin.
- It shows what reduced juice or a generous parlay price costs you before you offer it.
- It explains why a quiet month can look worse than it really was.
Check the overround on the markets your players use most. Track the hold over months, not weeks. And put the two numbers side by side: the gap between them shows how balanced your book actually is.