Accumulators, doubles and trebles

An accumulator combines several selections into one bet; every leg must win. The odds multiply, which is why accas produce big returns and lose most of the time.

The arithmetic

Convert each price to decimals and multiply. Four selections at 2/1, 6/4, 11/10 and evens: 3.0 × 2.5 × 2.1 × 2.0 = 31.5. A £5 four-fold returns £157.50.

Why the margin compounds

The bookmaker’s margin sits inside every price. If each leg carries a 5 per cent margin, a four-fold carries roughly 19 per cent, a six-fold about 27 per cent. Accas are the bookmaker’s most profitable product for that reason, and why they are promoted so hard.

Doubles, trebles and combination bets

A double is two legs, a treble three. Combination bets cover every double, treble and so on among a set of selections: a Yankee is 11 bets on four selections (6 doubles, 4 trebles, 1 four-fold), a Lucky 15 adds the 4 singles. They return something if some legs win, at a much higher total stake.

Acca insurance, boosts and cash out

Acca insurance refunds the stake as a free bet if one leg loses, usually with a minimum number of legs and minimum odds. Boosts add a percentage to the winnings, capped. Cash out offers a price to settle early; the offer is always below the fair value of the remaining legs, which is how the bookmaker earns on it.

Use the accumulator calculator to check a return before you place it.