Calculate the bookmaker's edge on any market, or load real match odds from our database.
Bookmaker margin — also called the overround or vig — is the built-in cut a book takes by pricing every outcome of a market slightly short of its true probability. When you add up the implied probabilities from every price in a market, a fair market totals 100%; the amount over 100% is the margin. This calculator turns your odds into that percentage and strips it out to show the no-vig "true" odds and implied probabilities behind the prices.
The margin is the bookmaker's edge baked into every price, so a lower margin means more of the true value stays on your side of the bet. Comparing the same market across books quickly shows which one is pricing it tightest. Margins vary a lot by sport, league and market depth — top football and tennis are often keenest, while niche outrights carry the most vig. A low margin improves your odds but never guarantees a winning bet.
Take a two-way market priced 1.95 / 1.95. Each side implies 1 / 1.95 = 51.28%, so the market totals 102.56% — a margin of 2.56%. Removing the vig splits the 100% fair line evenly, giving no-vig true odds of 2.00 / 2.00 (50% each). A sharper book at 2.00 / 2.00 would carry no margin at all.
Calculate the bookmaker's edge on any market, or load real match odds from our database.
Bookmaker margin — also called the overround or vig — is the built-in cut a book takes by pricing every outcome of a market slightly short of its true probability. When you add up the implied probabilities from every price in a market, a fair market totals 100%; the amount over 100% is the margin. This calculator turns your odds into that percentage and strips it out to show the no-vig "true" odds and implied probabilities behind the prices.
The margin is the bookmaker's edge baked into every price, so a lower margin means more of the true value stays on your side of the bet. Comparing the same market across books quickly shows which one is pricing it tightest. Margins vary a lot by sport, league and market depth — top football and tennis are often keenest, while niche outrights carry the most vig. A low margin improves your odds but never guarantees a winning bet.
Take a two-way market priced 1.95 / 1.95. Each side implies 1 / 1.95 = 51.28%, so the market totals 102.56% — a margin of 2.56%. Removing the vig splits the 100% fair line evenly, giving no-vig true odds of 2.00 / 2.00 (50% each). A sharper book at 2.00 / 2.00 would carry no margin at all.