What is vig in betting? The charge inside every price

The short answer

Vigorish, juice, margin, the cut: they all name the same thing. A sportsbook offers prices slightly worse than the true probabilities of the outcomes, and the difference is what it keeps for accepting the bet. Nothing is deducted from a winning ticket. The charge is already inside the price, which is why nobody ever sees a line item for it.

A point spread is designed to be a coin flip. If it were priced fairly both sides would be +100, an even-money bet. They are priced at −110, so you risk $110 to win $100 on either side. That extra ten dollars, on both sides of the market, is the vig.

Measuring it

Convert each price to its implied probability and add them up. At −110 the implied probability is 52.38%, and two sides of that market sum to 104.76%. A fair market would sum to exactly 100%. The 4.76% excess is the overround.

There is a second figure and the American industry uses the same word for it. The hold is the share of every dollar staked that the book expects to keep, and on the same market it is 4.55%. The relationship is fixed: hold equals overround divided by one plus overround. They are close at small margins and they drift apart as margins grow, so on a wide prop the difference is material.

This is why a serious answer to what is vig in betting has to name which number is meant. Quote 4.76% and you are describing how far the prices sit from honest. Quote 4.55% and you are describing what it costs you to bet into them. The vig calculator prints both, labelled, from any set of prices.

What normal looks like

Main markets on major American sports sit near a 4.5% hold. That is the tightest pricing an ordinary account reaches, and it exists because those markets carry enormous volume and books compete on them directly.

Three-way markets add an outcome and therefore another price to load, so soccer full-time results and hockey regulation results typically run 6% to 8%. Player props are wider again, often 8% to 20%, and they are presented in exactly the same visual style as a spread with nothing on the screen to signal the difference.

Parlays are where it compounds. Each leg carries its market’s margin and multiplying legs multiplies margins, so three −110 legs turn a 4.55% hold into 13.03% and eight turn it into 31.08%. The bet looks the same on the slip and costs roughly seven times as much.

Why it is worth measuring before betting

The margin decides the win rate you need. At −110 a bet has to land 52.38% of the time simply to break even, and a genuine coin flip lands 50% of the time. The gap between those two numbers is small per bet and it is the entire reason the house side of the business works.

It also decides what comparison between sportsbooks means. One book at −108 and −112 and another at −105 and −115 are not offering the same market, and reading the headline price on your side will not tell you which is cheaper. Strip the margin from both and the answer is immediate.

None of this is concealed. Every price is published, and the arithmetic takes seconds. What makes vig easy to overlook is that it never appears as a charge: there is no fee line, no commission, and no moment where money visibly leaves for it. It is simply that the price was always slightly worse than the event deserved, on both sides, every time.

One more thing follows from the fact that the charge sits in the price. Because every bet carries it, win or lose, volume matters more than results. A bettor who breaks even on outcomes still pays the margin on everything staked, and a bettor who doubles their number of bets doubles what they pay regardless of how those bets land. That is the mechanism, and it is why turnover, and not luck, is the variable that decides the long-run figure.

It also explains the shape of sportsbook marketing. Promotions push volume and not size, because each additional bet is another turn of the same wheel. None of that is a criticism; it is simply what a margin business looks like from the inside, and it is fully visible in the prices.

The practical response is not complicated. Measure the market before betting it, prefer tighter markets when the alternative is equivalent, and treat a wide market as something that has to be worth more to be worth the same. The vig calculator takes every price in a market and returns both figures, which is about ten seconds of work for a number that applies to every bet placed into it.