How to Remove the Vig From Betting Odds
Sportsbook prices include a margin on every outcome. Here is how to strip it out and find the fair probability underneath, using the proportional method with worked examples.
Updated 5 min read
Every sportsbook price contains two things that look like one number. There is an estimate of how likely the outcome is, and there is a charge for being allowed to bet on it. Almost every useful piece of betting analysis starts by pulling them apart.
Where the margin shows up
Take a standard point spread, priced -110 on both sides. Convert each to implied probability:
probability = |odds| ÷ (|odds| + 100) → 110 ÷ 210 = 52.38%
Both sides are 52.38%. Added together: 104.76%.
A market covering every possible outcome should sum to exactly 100%, because something has to happen. The 4.76 percentage points above that is the overround, and it is the sportsbook's margin. Charge it on both sides and the book profits regardless of which way the game goes, provided the money is balanced.
| Market type | Typical total | Approximate vig |
|---|---|---|
| Point spread (-110 / -110) | 104.8% | 4.5% |
| Competitive moneyline | 104% – 106% | 4% – 6% |
| Player props | 106% – 112% | 6% – 11% |
| Same-game parlay legs | 110%+ | 9%+ |
The proportional method
The standard way to remove the vig. Three steps.
- Convert every outcome in the market to its implied probability.
- Add them to get the total (the overround).
- Divide each probability by the total.
The results sum to 100%, and each one is the fair probability that outcome implies.
Example: a symmetric market
Both sides at -110.
| Step | Side A | Side B |
|---|---|---|
| Implied probability | 52.38% | 52.38% |
| Total | 104.76% | 104.76% |
| Divided by total | 50.00% | 50.00% |
Fair price: +100 on both sides. Unsurprising, but it confirms the method.
Example: an asymmetric market
Favourite at -140, underdog at +120.
| Step | Favourite (-140) | Underdog (+120) |
|---|---|---|
| Implied probability | 140 ÷ 240 = 58.33% | 100 ÷ 220 = 45.45% |
| Total | 103.79% | 103.79% |
| Divided by total | 56.20% | 43.80% |
So the sportsbook's genuine estimate is 56.2% / 43.8%, not 58.3% / 45.5%. In no-vig American odds, that is about -128 and +128.
This matters. If you thought the favourite was a 58% shot, the raw price of -140 looks like no edge at all. Against the no-vig number of 56.2%, you have a small one.
Three-way markets
Soccer and other sports with a draw work identically; there is just one more term. A market at +150 / +220 / +180:
| Outcome | Price | Implied | No-vig |
|---|---|---|---|
| Home | +150 | 40.00% | 38.4% |
| Draw | +220 | 31.25% | 30.0% |
| Away | +180 | 35.71% | 34.3% |
| Total | 106.96% | 100% |
A 6.96% overround — noticeably more than a two-way spread, which is typical of three-way pricing.
What the no-vig number is for
Comparing sportsbooks honestly. Two books can post different prices with identical opinions, because they charge different margins. Stripping the vig from both tells you whether they actually disagree about the game. When they do disagree, one of them is offering a price the other thinks is wrong.
Checking your own view. The only reason to place a bet is a belief that the outcome is more likely than the price says. Measuring that against the raw price is measuring against a number that includes a fee. The no-vig probability is the right comparison.
Finding the sharp number. The no-vig price at a high-limit sportsbook close to kickoff is the best publicly available estimate of a game's true probability. It is a more reliable benchmark than most models, and it is free.
Putting it to work
The practical routine is short:
- Find the market at two or three sportsbooks.
- Remove the vig from each.
- If one book's no-vig probability differs meaningfully from the others, that is the interesting one.
- Check whether the raw price at that book beats the consensus no-vig probability. If it does, the bet has positive expected value.
Step four is the one people skip. A good no-vig number at a book whose posted price is still worse than the fair probability is not a bet — it is a book being slightly less wrong than its competitors while still charging you.
Related reading
- Line shopping: why the best price matters more than the best pick — the habit that turns the above into money.
- Expected value in sports betting — the calculation that step four is describing.
- How to read American betting odds — the conversions this article assumes.
Frequently asked questions
- What is the vig in sports betting?
- The vig — also called juice or the overround — is the sportsbook's built-in margin. It is the amount by which the implied probabilities of all outcomes in a market exceed 100%. A standard -110 two-way market totals 104.76%, so the vig is about 4.76%.
- How do you calculate no-vig odds?
- Convert each outcome to implied probability, add them to get the total, then divide each probability by that total. The results sum to 100% and represent the fair probabilities. Convert back to odds to get the no-vig price.
- Why remove the vig?
- The posted price mixes the sportsbook's probability estimate with its margin. Removing the vig isolates the estimate, which is what you need to compare against your own view or against another sportsbook's number.
- What is a typical vig percentage?
- Around 4.5% to 5% on standard point spreads and totals at major sportsbooks. Moneylines on lopsided games, player props and same-game parlays commonly run 6% to 10% or higher.
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BestSlip Analytics Desk
Odds & Analytics
The analytics desk covers the measurement side of betting — implied probability, vig removal, expected value, return on investment and sample size. The work is descriptive: it explains how a number is calculated and what it can support, never what anyone should wager.
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