If you only ever learn one thing about how sportsbooks make money, make it this. The vig — also called the juice, the cut, or the hold — is the fee the book bakes into every price it offers. It is small enough to ignore on any single bet and large enough to quietly bankrupt you over a season. Most losing bettors never lose because they pick badly; they lose because they pay this tax over and over without ever seeing it. This course makes it visible, shows you how to measure it, and shows you why beating it is the entire game.
What the vig actually is
Look at a standard point-spread market. Both sides are usually priced at −110: you risk $110 to win $100 whether you take the favorite or the underdog. It looks like a fair, even market — two sides of a coin. It isn’t.
Recall from Course 01 that every price hides an implied probability. The implied probability of −110 is 110 ÷ 210 = 52.38%. But there are two sides, and both are −110, so the book is implying each outcome happens 52.38% of the time. Add them up:
Implied probability from American odds
Negative odds: |odds| ÷ (|odds| + 100) Positive odds: 100 ÷ (odds + 100)−110 → 110 ÷ 210 = 52.38%. Two sides → 52.38% + 52.38% = 104.76%.
The two probabilities sum to 104.76%, not 100%. A real coin flip can’t land on heads and tails 104.76% of the time — the extra 4.76% isn’t probability at all. It’s the sportsbook’s margin. That surplus is the vig, and it’s why the −110/−110 market is not a 50/50 proposition.
The break-even win rate
Here is where the vig stops being abstract. Because you risk $110 to win $100, a winning bet and a losing bet don’t cancel out evenly. Win one, lose one, and you’re down $10. So winning exactly half your bets is a losing strategy.
The win rate you actually need just to break even is the same 52.38% the price implied:
Break-even win rate at −110
break-even % = 110 ÷ (110 + 100) = 52.38%Think about what that gap means. To make money betting −110 lines, you must win more than 52.4% of them — not 51%, not 52%. A bettor who is genuinely 50/50 — flipping a coin, or picking with zero edge — does not break even. They bleed money at a steady, predictable rate, and the only thing the book had to do was set the price at −110 instead of even money.
This single fact is why “I went 50-50 last month” is not breaking even. It’s a loss.
The no-vig (fair) price
If the book’s two implied probabilities sum to more than 100%, then neither number is the book’s true estimate of how likely each side is — both are inflated by the margin. To recover the book’s honest opinion, you strip the vig out by normalizing: divide each side’s implied probability by the total of the two, so they’re forced back to summing to 100%.
No-vig (fair) probability
no-vig % = (side’s implied %) ÷ (sum of both implied %)On a perfectly symmetric −110/−110 market this just hands each side 52.38 ÷ 104.76 = 50% — exactly what you’d expect. It gets interesting on a lopsided market, where the two sides carry different prices.
Worked example — an uneven market
A market is posted at −140 on the favorite and +120 on the underdog. Find the book’s true (no-vig) estimate for each side.
- Step 1 — implied probabilities. Favorite: 140 ÷ (140 + 100) = 140 ÷ 240 = 58.33%. Underdog: 100 ÷ (120 + 100) = 100 ÷ 220 = 45.45%.
- Step 2 — add them up. 58.33% + 45.45% = 103.79%. The overage of 3.79% is this market’s hold.
- Step 3 — normalize each side. Favorite: 58.33 ÷ 103.79 = 56.2%. Underdog: 45.45 ÷ 103.79 = 43.8%.
- Check: 56.2% + 43.8% = 100%. The vig is gone.
So once you remove the margin, the book really thinks the favorite wins about 56.2% of the time — not the 58.33% the raw price suggested. That 56.2% is the number you should compare against your own estimate, and against other books, when you’re hunting for value.
Hold varies wildly by market
Not all vig is created equal. The 4.76% on a standard −110/−110 spread is roughly the cheapest tax you’ll pay. The hold climbs fast as the bet gets more exotic:
- Straight sides & totals (spreads, totals, two-way moneylines) — typically a 4–5% hold. This is the bettor-friendly end of the menu.
- Player props & alternate lines — often 6–8% or more. Less efficient markets, fewer competing bettors, fatter margins.
- Longshots & futures — can run well into double digits. A 20-team “who wins the title” market might hold 20–30% across all the outcomes combined.
- Parlays — the vig compounds on every leg. Because each leg is already priced with its own hold, stringing legs together multiplies the margin. A modest per-leg edge for the book becomes a brutal edge over a multi-leg ticket.
The rule of thumb: the more legs, the more tax. A four-leg parlay isn’t paying one vig — it’s paying four, stacked. That’s exactly why books advertise parlays so aggressively and why they’re the house’s favorite product.
Why it compounds
A 4.76% hold sounds trivial. On one $110 bet it’s a rounding error. The problem is volume. The vig isn’t charged once — it’s charged on every single wager you make, win or lose, forever.
Place a few hundred bets over a season and that small, ignorable fee gets applied a few hundred times. It grinds against your bankroll the same way a casino’s house edge grinds against a roulette player: slowly, relentlessly, and with near-perfect consistency. The book doesn’t need you to lose any one bet — it just needs you to keep betting into a margin. Over a large enough sample, the math does the rest.
This is the core reason most bettors are long-term losers. They’re not unlucky and they’re not stupid. They’re paying a 4.76% (or 8%, or 25%) tax on enormous volume, and they never subtract it from their mental scorecard.
Beating the vig
If the vig is the tax, the rest of this site is about how to beat it. There are three weapons, and the remaining Foundation and Sharp-Play courses each take one in depth:
- Line shopping (Course 08) — the same bet is priced differently at different books. Always taking the best available number directly shrinks the vig you pay, bet after bet.
- Finding value / +EV (Course 07) — once you can compute a no-vig fair price, you can spot the times a book’s price is better than the true probability. Bet only those, and the math finally tilts your way.
- Promotions & bonuses (Course 09) — boosts, free bets, and bonuses are the book paying you a margin. Used correctly, they can more than cancel the vig on a given wager.
Every one of those tools is, at its heart, a way of overcoming this one number. Master the vig and the rest of betting strategy snaps into focus: the whole game is paying less of it than the other guy.
Common mistakes
- Treating −110 as a 50/50 proposition. It implies 52.38% per side and sums to 104.76%. The “coin flip” already has the house’s thumb on it.
- Comparing two books’ raw prices without removing the vig. A −140 at one book and a −135 at another aren’t comparable until you’ve normalized both to their no-vig probabilities.
- Ignoring the much higher hold on parlays and props. A four-leg parlay can carry several times the margin of a straight bet. The fun ticket is the expensive one.
- Assuming you only need to win half your bets. At −110 you need to clear 52.4% just to break even. Going 50/50 is a slow, guaranteed loss.
Key takeaways
- The vig is the book’s built-in fee — on a −110/−110 market the two implied probabilities sum to 104.76%, and that extra 4.76% is the hold.
- Break-even at −110 is 52.38%, not 50% — winning exactly half your bets loses money.
- Strip the vig by normalizing: divide each side’s implied probability by the sum of both, so they total 100%. That’s the book’s true estimate.
- Hold is small on straight sides and much larger on props, longshots, and parlays — and it compounds over volume, which is why most bettors slowly lose.