How to see the margin
Take a 1X2 market priced 2.10, 3.40 and 3.60. The implied chances are 47.62%, 29.41% and 27.78%. Together: 104.81%. The 4.81% above 100 is the margin. Put the prices into the margin calculator and it does this for you.
What it costs you
A 4.81% overround means the bookmaker pays back about 95.4% of the money staked on that market over time. If you bet ₦100,000 a month into such markets at random, the expected cost is about ₦4,600.
Why accumulators multiply it
Each leg in an acca passes on its own margin. If every leg returns 95% of fair value, the acca returns 0.95 × 0.95 × ... for every leg:
| Legs | Share of fair value | Hidden cost |
|---|---|---|
| 1 | 95.0% | 5.0% |
| 3 | 85.7% | 14.3% |
| 5 | 77.4% | 22.6% |
| 8 | 66.3% | 33.7% |
| 12 | 54.0% | 46.0% |
That is why a long acca can look generous and still be poor value. Acca bonuses exist partly to make up for this.
How to use the margin
- Compare bookmakersThe same market at two bookmakers can carry very different margins. Lower is better for you.
- Compare marketsMain markets on big matches usually carry lower margins than specials and long lists of outcomes.
- Find fair oddsRemove the margin to estimate the real chance, then judge prices against it.
Our margin calculator spreads the margin in proportion to the odds. Real bookmakers often load more of it on long prices, so treat the fair odds of outsiders with care.
Questions
Can the margin be negative?
Within one bookmaker, almost never. Across bookmakers, picking the best price for each outcome can push the total under 100%: that is an arbitrage.
Is overround the same as margin?
People use both words. Strictly, overround is the book above 100% (4.81% here); some sources quote the margin as 1 minus the payout rate (4.59%).
Does a low margin mean a bet will win?
No. It only means you pay less for the bet.