No-Vig Fair Odds Calculator
Strip the bookmaker’s margin from any market to reveal the true fair odds and genuine probability of each outcome. Compare markets and find the lowest-margin bookmakers instantly.
Enter the decimal odds for every outcome in a market. The calculator removes the bookmaker margin (vig) to show you the true fair odds and genuine implied probability for each selection.
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What Is the Vig (Bookmaker Margin)?
The vig — short for vigorish, also called the overround or bookmaker margin — is the built-in profit margin that every bookmaker embeds into their odds. It ensures that no matter which outcome occurs, the bookmaker makes money over a large enough sample of bets. The vig is the reason why if you add up the implied probabilities of all outcomes in any market, the total always exceeds 100%.
In a perfectly fair market (like a coin flip), each side would be offered at 2.00 (Evens), with implied probabilities summing to exactly 100%. A bookmaker might instead offer 1.91 on both sides — implied probabilities of 52.36% each, totalling 104.72%. The excess 4.72% is the margin. Our no-vig calculator removes this excess and converts the bookmaker’s prices back to fair odds.
How to Calculate Fair Odds (No-Vig)
The no-vig calculation involves three steps:
- Step 1 — Sum implied probabilities: For each outcome, calculate 1 ÷ Decimal Odds. Sum all these figures. If the market has a 5% margin, this sum equals 1.05.
- Step 2 — Normalise: Divide each outcome’s implied probability by the total sum. This gives the fair probability with margin removed.
- Step 3 — Convert back to odds: Divide 1 by each fair probability to get the fair decimal odds.
For a two-outcome market with odds of 2.10 and 3.60: Implied probabilities are 47.62% and 27.78%, totalling 75.40% — wait, that is below 100%, which means an arbitrage opportunity exists. More typically: home 1.80 (55.56%), draw 3.50 (28.57%), away 4.50 (22.22%) — total 106.35%, margin 6.35%. Our calculator strips this instantly.
Why Does This Matter for UK Bettors?
Understanding the margin on any market helps you make better decisions about where to bet and whether odds represent fair value. A typical major UK bookmaker charges a 5-8% margin on standard football markets. Betting exchanges like Betfair charge commission of 2-5% on winnings but offer genuine fair market odds — often better value than traditional bookmakers. Our arbitrage calculator identifies when odds discrepancies between bookmakers create a guaranteed profit opportunity.
Comparing Bookmaker Margins
Not all bookmakers charge the same margin on every market. Lower-profile leagues and less popular sports often carry higher margins. Big football markets on Premier League matches typically have margins of 3-6% at major operators. In-play markets carry higher margins because the bookmaker is managing risk in real time. Use this calculator to compare margins across bookmakers on the same market to identify who is offering the best value before placing.
No-Vig Odds and Value Betting
Once you know the fair odds for a selection, you can compare them against bookmaker prices across multiple operators. Any bookmaker offering better than fair odds on a selection is giving you a positive expected value bet. Combine this with our expected value calculator to quantify exactly how much edge you have, then use our bankroll management calculator to size your stake optimally using the Kelly Criterion.
No-Vig and Matched Betting
Matched bettors use no-vig calculations to assess the quality of bookmaker promotions. An enhanced price offer is only genuinely valuable if the enhanced odds are meaningfully above the no-vig fair price. Use this calculator alongside our free bet calculator and matched betting calculator to evaluate the full value of any promotional offer.
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The vig (vigorish) is the bookmaker’s built-in profit margin, also called the overround. It is the reason the implied probabilities of all outcomes in a market sum to more than 100%. A typical UK bookmaker charges a 3-8% vig depending on the sport and market.
Calculate the implied probability for each outcome (1 ÷ Odds), sum all probabilities, then divide each individual probability by the sum. Convert back to odds by dividing 1 by each fair probability. Our calculator does this automatically for 2-10 outcomes in any market.
For major football markets (Premier League), typical margins range from 3-6%. For horse racing, margins are often higher at 15-20% on win markets. Betting exchanges charge commission of 2-5% on winnings but offer near-fair market odds, making them generally better value than bookmakers for frequent bettors.
If the implied probabilities of all outcomes from different bookmakers sum to less than 100%, an arbitrage opportunity exists. This calculator shows you the implied total for a single bookmaker’s market. Use our dedicated arbitrage calculator to input odds from multiple bookmakers and calculate guaranteed profit and optimal stakes.
The no-vig calculation works most cleanly in decimal format. Use our odds converter to instantly translate fractional or American odds to decimal before entering them here.