Fair Odds & No-Vig Explained
Learn how to see through the bookmaker's built-in profit margin.
What is the "Vig"?
The "vig" (short for vigorish), also known as overround or the bookmaker's margin, is the commission a bookie bakes into their odds to guarantee a profit. It's the reason why the probabilities of all outcomes in an event always add up to more than 100%.
For example, in a tennis match, a bookmaker might offer odds of **1.91** on Player A and **1.91** on Player B. The implied probability for each is `(1 / 1.91) * 100 = 52.3%`. The total market is `52.3% + 52.3% = 104.6%`. This extra **4.6%** is the vig. It's the "price" you pay to place a bet.
Finding the "Fair" Odds
"Fair odds" represent the true probability of an event, where the total market adds up to exactly 100%. To find them, we must mathematically remove the vig.
The process is:
- Calculate the implied probabilities for all outcomes (e.g., 52.3% and 52.3%).
- Sum them up to find the total market (104.6%).
- Normalize each probability by dividing it by the total market (e.g., `52.3% / 104.6% = 50%`).
- Convert these new "fair" probabilities back into odds (e.g., `1 / 0.50 = 2.00`).
In our example, the true, fair odds of the 1.91 vs 1.91 market are actually **2.00 vs 2.00**.
Why is This Important?
- To Find True Value: You can only know if a bet has value by comparing your own probability assessment against the *fair odds*, not the odds inflated with vig.
- To Compare Bookmakers: By calculating the vig, you can easily see which bookmakers offer better prices (lower vig). A bookie with a 2% vig on a market is far superior to one with an 8% vig.
How This Connects to Our Tool
Manually calculating the vig and fair odds for every market is tedious. Our **No-Vig Calculator** is built to do this for you instantly. Simply input the odds for all outcomes of an event, and it will show you:
- The bookmaker's total vig percentage.
- The true, fair probability for each outcome.
- The corresponding "no-vig" fair odds.
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