Commercial
Vigorish (Vig)
Reviewed by iGaming Times editorial teamLast reviewed 24 September 2026
What is Vigorish?
The American term for a bookmaker’s built-in margin, expressed through the price rather than charged as a fee. Also called juice. The equivalent concept to overround.
Key takeaways
- Vigorish, also called vig or juice, is the bookmaker's margin built into the odds rather than charged as a fee.
- Standard -110 pricing on both sides of a market implies about 52.4% each, a combined 104.8%.
- Vig is the American name for overround and a clear measure of how competitive a betting market is.
Why it matters
Vigorish is the same idea as overround approached from the other end. A perfectly balanced two-way market would price both sides at even money; an American book prices them at -110 each, meaning a bettor risks $110 to win $100. Those prices imply 52.4% probability each, totalling 104.8%, and the 4.8% above 100% is the vig. The bookmaker does not charge a commission; it is embedded in the odds.
The vocabulary matters when reading cross-market coverage, because European and American writers describe the identical economics in different units and the numbers do not look comparable. It also matters commercially, because vig is the clearest measure of competitive intensity in a market. Standard -110 pricing has held for decades on major American sports, while newer entrants have used reduced-juice pricing as an acquisition tool, and parlays carry far higher effective margins than their component legs. Prediction-market exchanges are a genuine structural challenge here, because an exchange charges a transaction fee rather than embedding a margin, so the headline price a participant sees is closer to the true probability. That comparison is doing a lot of the work in the argument over whether event contracts will take share from sportsbooks.
The bottom line
Vig is overround in American clothing. It is also the cleanest number for comparing how competitive a betting market actually is.
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Frequently asked questions
What is vigorish in sports betting?
Vigorish, shortened to vig and also called juice, is the margin a bookmaker builds into its prices. Rather than charging a commission, the book prices each outcome slightly shorter than its true chance, so the implied probabilities add up to more than 100%. It is the American term for the same economics that European writers call overround.
How is the vig calculated on a -110 line?
Convert each price to an implied probability. At -110 a bettor risks 110 to win 100, so the implied probability is 110 divided by 210, about 52.4%. With both sides at -110 the total is about 104.8%, and the 4.8 points above 100% are the vig expressed as overround. On perfectly balanced action the bookmaker keeps about 4.5% of stakes.
What is the difference between vigorish and overround?
They describe the same thing from different starting points. Overround is the European term and is usually quoted as the percentage by which a market's implied probabilities exceed 100%. Vigorish is the American term, often discussed through the standard -110 price. Because the two are quoted in different conventions, American and European figures can look different even when the pricing is identical.