Guide · 7 min read
Bookmaker margin and overround: how to calculate it from the odds
Every price a bookmaker shows contains a mark-up. You can measure it in under a minute with nothing but the odds. This guide gives the formula for the overround, the payout rate and the margin, works through two-way and three-way examples, shows how markets differ, and explains what Austria's 5% betting fee does to the numbers.
Updated 22 October 2026
Contents
Margin calculator
Enter the decimal odds of every outcome in one market at one bookmaker to see the book sum, the payout rate and the margin, plus fair odds with the margin spread proportionally across the outcomes.
Overround, payout rate and margin: the formula
Convert each price in a market into its implied probability (1 / odds) and add up all outcomes. Without a mark-up that sum would be exactly 100%. Everything above it is the bookmaker's margin, also called the overround, the vig or the juice.
Book sum (overround): S = Σ (1 / odds)
Payout rate = 1 / S
Margin = 1 − payout rate
Two numbers are both called "margin" in practice: the overround S − 1 (how far the probabilities exceed 100%) and 1 − payout rate (the share of stakes the bookmaker keeps on a perfectly balanced book). We use the second here because it translates directly into euros. In German-speaking countries the payout rate is known as the Quotenschlüssel or Auszahlungsschlüssel. If S drops below 1 when you take the best price for each outcome across several bookmakers, you have a sure bet.
Worked examples
S = 1/1.90 + 1/1.90 = 0.5263 + 0.5263 = 1.0526 (105.3%).
Payout rate = 1 / 1.0526 = 95.0%. Margin = 5.0% (overround 5.3%).
Stake €100 on each side and you pay in €200 and get €190 back whatever happens. The €10 difference is 5% of your stake.
S = 0.4762 + 0.2941 + 0.2778 = 1.0481.
Payout rate = 1 / 1.0481 = 95.4%. Margin = 4.6%.
With two equal prices the payout rate is simply half the odds:
| Odds (2 outcomes) | S | Payout rate | Margin |
|---|---|---|---|
| 2.00 / 2.00 | 100.0% | 100.0% | 0.0% |
| 1.95 / 1.95 | 102.6% | 97.5% | 2.5% |
| 1.90 / 1.90 | 105.3% | 95.0% | 5.0% |
| 1.85 / 1.85 | 108.1% | 92.5% | 7.5% |
| 1.80 / 1.80 | 111.1% | 90.0% | 10.0% |
The classic American price of −110 on both sides (decimal 1.909) gives S = 104.8% and a payout rate of 95.5%. See odds formats for the conversion.
Step by step by hand
- Take every outcome of one market at one bookmaker, for example home, draw and away.
- Work out 1 / odds for each price and add the results to get S.
- Payout rate = 1 / S. The closer to 100%, the smaller the margin.
- Repeat for other bookmakers in the same market. The one with the higher payout rate returns more on average.
A caveat: a payout rate always describes a whole market. A bookmaker can run 95% overall and still have the best price in the market on one single outcome. Those individual outliers are exactly what makes sure bets possible.
Typical margins by market
The margin depends more on the market than on the bookmaker's name. These are rough observations, not official statistics:
- Main markets in top leagues (1X2, handicap and totals in the Premier League, Bundesliga, Champions League): a bookmaker's lowest margins, often around 3% to 6% at large international bookmakers, and lower at books that deliberately run very tight prices.
- Lower leagues and side markets (second divisions, corners, cards, player props): usually clearly higher, because there is less information and less turnover to spread the risk.
- In-play: often higher than pre-match, because prices change fast and the bookmaker protects itself against delayed data.
- Outrights (league winner, World Cup winner): frequently double-digit margins, because many outcomes are in play.
When in doubt, measure it: note the prices at two or three bookmakers for one market and calculate S. It takes a minute.
Why local bookmakers often run higher margins
In Austria, tipp3 (run by Österreichische Lotterien and Novomatic) and other brands with a strong retail network offer sports betting; in Slovakia, Tipos is the state lottery company's brand. In our experience such bookmakers often price with higher margins than large international online bookmakers. There is no public, maintained margin register, so we don't quote a percentage here; measure the market you care about with the method above. Plausible reasons:
- Bet slips in retail outlets stay valid for longer, and prices there can't be changed every second. A higher mark-up absorbs that.
- Customers come for the brand, the shop and habit, not for the best price.
- Less pressure from odds comparison in small markets.
A higher margin doesn't automatically mean worse individual prices. Slower updates can even leave single outcomes above the market average for a while. How that happens is explained in how bookmakers set odds.
Best prices across bookmakers: a lower combined margin
Margins add up for the bettor who stays with one bookmaker. Take a tennis match at two books:
| Bookmaker | Player 1 | Player 2 | Payout rate |
|---|---|---|---|
| Bookmaker A | 1.95 | 1.87 | 95.5% |
| Bookmaker B | 1.85 | 1.98 | 95.6% |
| Best of both | 1.95 | 1.98 | 98.2% |
Each book alone keeps about 4.5% on a balanced book; the best prices combined leave only about 1.8%. If the best prices pushed S below 1, the payout rate would exceed 100% and the gap would be a sure bet.
Margin and Austria's 5% betting fee
In Austria the bookmaker has owed a betting fee (Wettgebühr) of 5% of the stake since 1 April 2025. If it absorbs the fee, it eats a large part of its margin. If it passes the fee on to you (deducted from the stake or the payout), your effective odds fall to odds × 0.95 and so does your payout rate:
Effective odds = 1.90 × 0.95 = 1.805. S = 2 / 1.805 = 1.108.
Payout rate = 95.0% × 0.95 = 90.25%. Of €200 staked, only €180.50 comes back whatever happens.
So always compare prices after deductions. Whether a bookmaker passes the fee on shows on the bet slip.
Why the margin matters to you
Every percentage point of margin is a point you hand over on average across many bets. Someone who always takes the best available price pays less margin than someone who sticks with one bookmaker. Taking the best available price across books is called line shopping. To strip the margin out and get a fair price, see no-vig fair odds.
ArbVantage compares the prices of many bookmakers and shows you where the combined book sum across bookmakers falls below 100%, then works out the stakes for each leg. Whether you place the bets is your decision, and prices can still change before the second leg.
FAQ
What is a good payout rate?
The closer to 100%, the better. On main markets in big leagues many international bookmakers sit roughly between 94% and 97%, with very sharply priced books above that. On side markets, in-play and outrights the payout rate is usually clearly lower.
Is the margin the bookmaker's profit?
Not directly. The margin is the share that stays with the bookmaker on a perfectly balanced book. Its real result depends on how stakes are spread, which outcomes win and how many customers estimate better than it does. Costs and levies such as betting fees come off on top.
How does the Austrian betting fee affect the payout rate?
If a bookmaker passes Austria's 5% betting fee on to you, your effective odds are 5% lower. A payout rate of 95% becomes 90.25%. If the bookmaker absorbs the fee itself, your payout rate stays the same.
How do I calculate the margin with three outcomes?
Exactly as with two: add up 1 / odds for home, draw and away and divide 1 by that sum. For 2.10 / 3.40 / 3.60 that gives 1 / 1.0481 = 95.4%, so a margin of 4.6%.
Sources
- Unternehmensserviceportal (USP), Austria: Wettgebührenabrechnung
- RIS: Gebührengesetz 1957, § 33 TP 17 (bets)
- Steven D. Levitt: Why are gambling markets organised so differently from financial markets? The Economic Journal 114 (2004)
As of October 2026. Margins by market are observations and change constantly; measure them for your own market.
Betting carries risk, sure bets included: odds change, bets get voided and accounts get limited. Only stake money you can afford to lose. Our responsible gambling page lists free, confidential help in Austria and Germany.
Not betting, legal or tax advice. 18+. As of October 2026.