Bookmaker margin is something every bettor has encountered at least once during their betting experience. Simply put, the margin is the guarantee that the bookmaker will earn a profit regardless of the outcome. Many experienced players consider the margin as the commission a bookmaker charges for providing its services.
The margin depends on the odds — the lower the odds, the higher the margin. You can understand how it works using a coin toss example, where the chance of landing “Heads” or “Tails” is 50/50.
A simple and clear example: a bet is placed on an even or odd number of points in a volleyball match. The chances are 50/50, and mathematically, the bookmaker should offer odds of 2.00 for both outcomes. However, in reality, this rarely happens — bettors are usually offered odds of 1.9. This means that after placing 100 identical bets, a player will only profit if 53 out of 100 bets win, instead of 50.
According to simple math, a high margin decreases a bettor’s long-term profitability. The average margin for bookmakers is between 5% and 10% for single bets. For live bets, the margin is even higher — often reaching 20%.
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Types of bookmaker margin
Margins are generally classified as:
- High-margin – 5% and above.
- Medium-margin – from 3% to 5%.
- Low-margin – up to 3%.
Most bookmakers operate with a medium margin between 3% and 5%. It’s worth noting that the margin directly affects the betting interest — the lower it is, the more appealing the event becomes.
Are there bookmakers without a margin?
Unfortunately for bettors, no — such bookmakers don’t exist. However, for certain events, bookmakers may offer odds without a margin, usually as part of promotional campaigns. The margin is necessary to reduce risks and prevent financial losses from fixed matches.
How to calculate the margin
Calculating the margin is a fairly simple process that doesn’t require special knowledge. You can use this basic formula:
where probability 1 = 1 / odds 1,
and probability 2 = 1 / odds 2.
Let’s take a football match with three possible outcomes as an example:
- Team 1 win (W1)
- Draw (X)
- Team 2 win (W2)
Example: (1/2.1 + 1/3.25 + 1/3.38 – 1) × 100 = 0.0797 × 100 = 8%.
(1/1.80 + 1/1.80 – 1) × 100 = 0.111 × 100 = 11.1%.
You can calculate the margin manually or by using online margin calculators. Among the most attractive events with low margins are the Champions League and the Stanley Cup.
How margin affects player profit
The bookmaker’s margin has a significant impact on player profitability. The higher the margin, the more successful bets are required to stay profitable.
The most balanced odds would be W1 (2.00) – W2 (2.00). In this case, regardless of how many bets a player makes, the return rate would be 50%. But here, the bookmaker earns nothing.
With a 5% margin, W1 (1.90) – W2 (1.90), the player must now win 23 bets instead of 20 to stay profitable. Many beginners don’t notice the difference between odds of 1.88 and 1.93, but it becomes significant over time.
By properly using the margin formula, you can find the most attractive odds for your bets.
Why you should know how to calculate the margin
Understanding how to calculate margin allows you to evaluate odds more effectively, analyze profitability, and avoid overpaying bookmakers. It also helps identify the most optimal betting opportunities.
The margin depends on the sport’s popularity and the tournament level. You should treat margin analysis rationally and carefully choose your bookmaker, considering multiple factors.
To ensure long-term profitability and enjoyment from betting, you can also use the ROI formula:
ROI values decrease as the margin increases, meaning you need to win more than half of your bets to stay profitable.
The ROI metric helps track your betting efficiency over time — showing whether your strategy works, whether it generates profit or losses. This formula is essential to maintain a long-term positive balance.
Read also: What is ROI in betting
