Accumulator Bets Explained: Why Bigger Payouts Mean Lower Win Chances

An accumulator combines several selections into one bet. The possible return rises because the odds are multiplied, but every leg normally has to win. That makes the chance of success fall quickly. In our simple example, five independent 50-50 selections have only a 3.125% chance of all winning. The bigger number on the bet slip does not make the bet more likely to win.

Key points

• An accumulator, acca, parlay or multiple combines two or more selections.
• The decimal odds are multiplied, and one losing leg normally loses the whole bet.
• Five independent 50-50 legs have only a 3.125% chance of all winning.
• Bookmaker margin can build across the legs, so the price deserves a careful look.

What an accumulator bet is

Each selection in an accumulator is called a leg. A double has two legs, a treble has three, and a five-fold has five. “Acca” is common in the UK, “parlay” in the United States, and “multiple” in other markets. The basic product is the same.

The selections usually come from different matches. A same-game product, often called a Bet Builder, combines outcomes from one match and needs special pricing because the legs may affect each other.

An accumulator is settled as one bet. If four legs win and the fifth loses, the usual result is no return.

How the odds and return are calculated

Multiply the decimal odds for every leg. Then multiply that combined price by the stake. Imagine five separate football selections, all priced at 1.90:

1.90 × 1.90 × 1.90 × 1.90 × 1.90 = 24.76

A €10 stake at 24.76 would show a possible total return of about €247.61, including the original stake. That applies only if all five selections win and the operator accepts and settles the bet.

The calculation is simple, but the large return can take attention away from the much smaller chance of collecting it.

Why the win chance falls so quickly