An accumulator, or acca, combines several selections into one bet. Every selection has to win, and the winnings from each leg roll on to the next, so the odds multiply. Two selections make a double, three a treble, four a fourfold, and so on.
How the odds multiply
Multiply the decimal odds of every leg to get the acca price. Four selections at evens (2.00) make 2 × 2 × 2 × 2 = 16.00, or 15/1, so a £5 fourfold returns £80.
| Legs at evens | Acca odds | £5 returns | Chance if each leg is 50% |
|---|---|---|---|
| 2 | 4.00 (3/1) | £20 | 25% |
| 3 | 8.00 (7/1) | £40 | 12.5% |
| 4 | 16.00 (15/1) | £80 | 6.25% |
| 5 | 32.00 (31/1) | £160 | 3.1% |
Why the margin grows with every leg
A genuine 50% chance should be priced at evens, but bookmakers usually offer something like 10/11 (1.91) and keep the difference. On a single, that costs you about 4.5% of your stake over time. Put four of those legs in an acca and the price is 1.91 × 1.91 × 1.91 × 1.91 = 13.31 instead of a fair 16.00, so the long-run cost rises to about 17%.
That is the trade-off: a big potential return from a small stake, paid for with a bigger built-in margin. Keep acca stakes small and fixed.
System bets: when one leg can lose
System bets cover every combination of your selections, so you can get a return without every leg winning. Each combination is a separate bet, so they cost more: a £1 Lucky 15 costs £15, not £1.
| Bet | Selections | Bets | Made up of |
|---|---|---|---|
| Trixie | 3 | 4 | 3 doubles and a treble |
| Patent | 3 | 7 | 3 singles, 3 doubles and a treble |
| Yankee | 4 | 11 | 6 doubles, 4 trebles and a fourfold |
| Lucky 15 | 4 | 15 | 4 singles plus the 11 bets in a Yankee |
How acca insurance works
Acca insurance is a bookmaker promotion: if one leg of a qualifying acca loses and the rest win, you get your stake back, usually as a free bet rather than cash. The terms decide what it is worth, so check:
- Minimum legs and odds: offers set a minimum number of selections, each above a minimum price.
- Refund type: a free bet usually pays only the winnings, not the stake, so a £10 free bet at evens returns £10, not £20.
- Maximum refund: there is normally a cap on the stake that is covered.
- Eligible markets: some offers only cover match-result selections.
Insurance softens the most painful result, losing by one leg, but it doesn't change the maths above: the more legs, the lower the chance of winning. Many bettors build accas from favourites or both teams to score picks; our staking plan treats them as small, speculative bets.
FAQs
What is acca insurance?
Acca insurance is a bookmaker offer that refunds your stake, usually as a free bet, if exactly one selection in a qualifying accumulator loses. The minimum number of selections, the minimum odds and the maximum refund vary between bookmakers, so read the terms before you place the bet.
What happens to an acca if a match is postponed?
Usually the postponed leg is made void and the acca is settled on the remaining selections, so a fourfold becomes a treble at lower odds. Bookmakers set their own time limits for rearranged matches, so check the rules if a game is moved.
How many bets is a Lucky 15?
A Lucky 15 is 15 bets on four selections: four singles, six doubles, four trebles and one fourfold. A £1 Lucky 15 costs £15 in total, and one winning selection is enough for a return, though not necessarily a profit.