Combination Bets Explained: How They Work, Risks & Strategy

If I had made this bet, I would have lost due to West Ham. The ref marked no goal and no penalty in stoppage time for the Hammers. Therefore, even though my winnings would have been multiplied by the combination bet, so was my implied probability. One loss wiped out the entire bet.

That’s the magic of combination bets. It’s possible to win higher amounts. The price paid, though, is a larger stake exposure and compounded probability.  

How Combination Bets Work

Credit: Boyle Sports - Screenshot captured by Samuel Barclay on 18 May 05:59

Combination bets come in various formats. This includes accumulators as well as betting systems like Lucky 63 betting. Some allow for partial wins and coverage, while others require all selections to win for a payout.

Regardless, when using any combination bet, implied probability is compounded. Therefore, the odds of 18/1, 11/10, and 17/10, would mean 5.26% x 47.62% x 37.04% = 0.93%. So the treble above has less than a 1% chance of hitting. 

Understanding Probability in Combination Bets

Knowing the mathematics behind combination probability can help showcase the pros and cons of such bets.

Converting odds to percentages is the first step. Manchester City at home was priced at 2/9 vs Southampton. 2/9 = 1.25. 1 ÷ 1.25 = 0.80 (80%).

When using combination bets, this percentage is multiplied by each selection. For example, 0.80 × 0.70 × 0.60 × 0.55 = 0.1848 (18.5%).

Credit: Samuel Barclay - Screenshot captured by Samuel Barclay on May 18 2026 - 06:51

As you can see, each selection lowers the probability rapidly. Even if selections appear strong individually, the probability can decrease quickly.

Remember, however, odds represent implied probability. They don’t represent certainty, and a bookmaker's margin is also in this percentage. 

How Bookmakers Price Combination Bets

Bookmakers' pricing on combination bets multiplies the odds across selections. Alongside this, margins compound too.

If a sportsbook builds a 5% margin into each leg (which is pretty normal), a four-fold can carry an overall margin of close to 18%.

Because of this, longer combinations at Premier League bookies become statistically more difficult even before variance is factored in. 

Why Combination Bets Appeal to Bettors

Larger Potential Returns

Combination bets multiply odds across selections, so a £5 stake could potentially produce a payout of hundreds or thousands. The trade-off, however, is that larger theoretical returns mean lower probability. 

Entertainment Value

If planned correctly, combination bets can be used across multiple fixtures over a weekend. Bets can include multiple fixtures from football, rugby, tennis, and more, keeping bettors engaged for a long period of time. 

Psychological Biases

Large wins can be appealing for some. They shouldn’t forget compounded risk, though. A slip of four 70% favourites offers an implied probability of about 24%. Such a low probability means it’s unlikely to win. 

Drivers of Value in Combination Bets

The value of combination bets comes from quality selections, not from chasing higher odds. Stronger slips that favour independent outcomes, moderate odds ranges, and selections that don’t move together are recommended. 

Risk & Bankroll Management

Disciplined risk helps absorb the higher variance in combination bets. Losses are expected, so they need to be planned for. Somebody with a £1,000 bankroll should try to keep to a 1% exposure (£10).

Remember, the more selections, the higher the variance. Implied probability suggests that the chances of winning a full payout are dramatically lower with each selection added.