An accumulator links several selections into one bet rather than placing a separate stake on each selection. In a standard multiple, every active selection must succeed for the bet to return money; one losing selection loses the multiple, as explained in William Hill's bet-type rules.
Start with that condition, not the largest number on the slip. A bigger potential return is not evidence that the selections are more convincing.
One bet, several conditions
Each selection is a leg: a particular outcome in a particular market. William Hill calls two selections a double, three a treble, and four or more an accumulator, although this site uses acca as a convenient umbrella label for its multiple-selection cards (William Hill's definitions).
The team name alone is not the selection. Team A to win, Team A or draw, and Team A to score over 1.5 goals ask different questions. Read the football markets guide if you cannot describe exactly what would make a leg win.
A hypothetical three-leg example
Suppose an ordinary treble contains decimal prices of 1.50, 2.00 and 2.50. This example assumes all three legs win, no leg is void and no special promotion changes settlement.
| Calculation | Result |
|---|---|
| Combined decimal price | 1.50 × 2.00 × 2.50 = 7.50 |
| Return from a hypothetical £2 stake | £2 × 7.50 = £15 |
| Profit after subtracting the original stake | £15 minus £2 = £13 |
The £15 is the total returned, not £15 profit plus the stake. The calculation follows the linked-return structure of an ordinary multiple described in William Hill's rules.
Try the arithmetic in the acca calculator without committing money. Compare the total return with the profit figure so the difference becomes familiar.
What a void leg changes
A void leg is not automatically a lost leg: William Hill's ordinary-multiple rules settle the bet on the remaining selections, turning a treble into a double (void-selection rules). In our hypothetical example, removing the 2.50 leg leaves 1.50 × 2.00 = 3.00, producing a £6 return and £4 profit from £2 if both remaining legs win.
Do not turn that example into a universal rule. Sky Bet distinguishes ordinary accumulators from certain in-play enhanced accumulators when postponements or abandonments occur, so the bookmaker, market and product terms matter (Sky Bet's postponement rules).
More legs mean more conditions
A hypothetical selection with a 60% chance does not make a three-leg acca 60% likely. If three such outcomes were independent, their combined chance would be 0.60 × 0.60 × 0.60 = 21.6%. This is an illustration of multiplication, not a forecast for any real card.
Related outcomes require particular care: William Hill's ordinary-multiple rules prohibit related contingencies such as a team winning 2-0 combined with that same team winning the match (related-contingency rules). Do not manually multiply same-match selections and assume a bookmaker must accept that price.
Check before you continue
- Identify every leg's market, selection and settlement period.
- Check the final kickoff, not just the first match: one card can span several days.
- Separate the quoted snapshot price from the price currently offered.
- Read the applicable void and special-product rules.
- Distinguish total return from profit.
Use the pre-bet checking guide to work through those questions in order. If you choose to gamble, set spending and time limits beforehand and do not chase losses, following GambleAware's advice.