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Vig Calculator: Sportsbook Margin on Any Market
By DeepChamp research team · Updated · Methods and limitations
Short answer
The vig is the margin an operator builds into a market. Enter the odds on each side and the calculator shows the overround, the margin as a percentage, and the extra probability you pay on every bet in that market.
Vig calculator
American odds.
American odds.
For a three-way result such as a draw.
| Side A at -110 | 52.38%fair probability 50.00% |
|---|---|
| Side B at -110 | 52.38%fair probability 50.00% |
| Implied probabilities added together | 104.76% |
| Margin (vig) as a share of the market | 4.55% |
| Expected cost of a 100 bet at fair probability | $4.55what the margin costs you before any edge |
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Researching a real market? Use the numbers in the app.
Download on the App StoreHow to use it
- 1Enter the American odds for both sides of the market, or all three outcomes for a three-way result.
- 2Read the margin: the lower it is, the less each bet costs you before any edge.
- 3Compare the same market across prices you can see to find the cheapest version of the bet.
- 4Remember that a lower margin only helps if you also have a view that differs from the market.
How the math works
A standard point spread priced at -110 on both sides has implied probabilities of 52.38 percent each, which sum to 104.76 percent. The excess, expressed as a share of the total, is about 4.5 percent, and that is the margin the operator keeps if the money is balanced.
Margin differs by sport, market and operator. Player props and alternate lines often carry more margin than main lines, so the cost of researching a niche market is not only your time but a higher break-even point.
- Overround
- overround = sum of implied probabilities
- Margin as a share of the total
- margin = (overround - 1) / overround
- Break-even at equal prices
- break-even = overround / 2 for a two-way market
Common questions
How do you calculate the vig on a bet?
Convert both sides to implied probabilities and add them. The amount over 100 percent is the vig expressed as an overround, and dividing that excess by the total gives the margin as a share of the market.
What is the vig on a -110 / -110 market?
Each side has an implied probability of 52.38 percent, so the total is 104.76 percent. The margin is about 4.5 percent of that total, which is why the break-even win rate is 52.38 percent rather than 50.
Is a lower vig always better?
It lowers the break-even point, which is good, but it does not create an edge on its own. A low-margin market is simply cheaper to be wrong in, and you still need a probability view that differs from the price.
This is educational research content. Examples use hypothetical numbers and are not live odds, picks, or claims about performance.
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