What Is Vig in Sports Betting? How Sportsbooks Build Their Edge

Vig, short for vigorish and also called juice, is the margin built into sportsbook odds. You usually see it through the prices rather than a separate charge on the bet slip. Understanding that margin explains why winning half your bets can still lose money and why a better price matters.

Three related quantities deserve separate names: the price of one wager, the overround across an entire market, and the sportsbook’s realized hold. All examples below are hypothetical standard cash wagers.

Why 50% wins lose money at -110

Take two $11 bets at -110. One wins and earns $10 profit; the other loses the full $11. The combined result is a $1 loss on $22 staked, despite a 1-1 record.

The break-even win rate is 110 ÷ (110 + 100) = 52.38%. This applies across equal-stake bets settling as wins or losses at that price, with no additional costs. Pushes return the stake and are excluded from that win-rate denominator.

Calling -110 “ten percent juice” because you risk $110 to win $100 can be misleading. The $10 difference is not the same measure as the market’s overround or the percentage of stakes the sportsbook retains.

Overround: add all implied probabilities

For a complete set of mutually exclusive outcomes, convert each price into an implied probability and add the results. A total above 100% shows overround. Use prices from the same market, rules and moment; mixing unrelated selections or outdated quotes produces a misleading result.

With both sides at -110, each implied probability is 110 ÷ 210 = 52.38095%. Their sum is 104.76190%, so the overround is 4.76190 percentage points above 100%, commonly quoted as 4.76%.

For a two-way spread that can push, this standard calculation treats the two prices on a decisive-result basis. A three-way moneyline requires all three outcomes, including the draw. A list of several futures contenders is insufficient if the full set of possible winners is missing.

Hold: what was retained from the money wagered

In a simple settled cash-bet example, realized hold is the sportsbook’s net wagering revenue divided by the total stakes, also called handle. This outcome-based measure differs from the overround visible in the odds. Accounting reports may use additional adjustments, so check their definitions. The Massachusetts Gaming Commission revenue glossary defines revenue hold using the licensee’s win divided by settled handle.

The same -110 market produces a different percentage

Suppose the book accepts $110 on each side of a two-outcome event, with no push, promotion or other adjustment. Total stakes are $220. The winning ticket receives $210: its $110 stake plus $100 profit.

The book retains $10. Its hold on this simplified market is $10 ÷ $220 = 4.55%, while the quoted overround is 4.76%.

If the stakes are uneven, the amount retained depends on which side wins. A real book’s hold can vary substantially and can be negative over a short period. It is also not net business profit after operating expenses.

No-vig probability: a market estimate after normalization

A simple way to remove overround is proportional normalization. Divide each raw implied probability by the sum of all the market’s raw probabilities. This makes the adjusted numbers total 100%.

For a hypothetical two-way moneyline of Team A -150 and Team B +130:

Using unrounded decimals, Team A’s adjusted estimate is 0.60 ÷ (0.60 + 0.4347826) = 0.5798319, or about 57.98%. This method assumes the margin is removed in proportion to the quoted probabilities.

That assumption is a convenience, not proof of how the sportsbook set its prices. Other no-vig methods can produce different estimates, particularly for unevenly priced outcomes. The underlying market can also be wrong. “No-vig” therefore describes an adjustment to prices, not a verified true probability.

A single price cannot reveal the entire market’s margin

A quote of -150 gives a 60% break-even threshold for that wager. It does not tell you the overround without the other outcome prices. Pairing -150 with +130 creates a different market margin from pairing it with +140.

Likewise, a positive price can include margin. The plus sign describes the payout ratio, not an exemption from the sportsbook’s advantage. To evaluate the exact wager, compare its offered price with a defensible estimate of its probability.

Compare prices without changing the stake

For an identical bet, a $10 stake at -105 earns about $9.52 profit if it wins. At -110 it earns $9.09; at -120 it earns $8.33. The break-even rates are approximately 51.22%, 52.38% and 54.55%, respectively.

You can instead compare the amount needed to win a fixed profit: earning $100 would require stakes of $105, $110 or $120. Keep that profit-target comparison separate from a fixed-stake comparison. Mixing the two makes the cost look smaller or larger than it is.

A better price improves the payoff on an otherwise identical ticket. It does not establish that the outcome is worth betting. Changing the threshold, period, participation rules or promotional terms can also make two superficially similar prices incomparable.

A lower margin can improve the terms available to a bettor, but it cannot make betting risk-free. Keep spending limits independent of how attractive a quote appears.

Use the offered price for your payout and break-even calculation, the complete market for overround, and settled stakes and returns for realized hold.

What to read next

• American odds and implied probability: work through the price conversions.
• Expected value: combine a probability estimate with the actual payout.
• Closing line value: see why the closing market’s margin affects percentage comparisons.