What is an accumulator?

An accumulator, or acca, is a single bet combining several selections. Every leg must win for the bet to pay, and each leg's winnings roll onto the next.

What are doubles, trebles and four-folds?

They are accumulators named by leg count: a double has 2 selections, a treble 3, a four-fold 4, a five-fold 5, and so on.

What happens to an acca if a match is postponed?

That leg is normally voided and settled at odds of 1.00, so it drops out of the calculation. A four-fold becomes a treble at the reduced combined price rather than losing outright. Check your bookmaker's rules, as they vary.

Is an accumulator the same as a parlay?

Yes. Accumulator is the UK and Irish term; parlay is the US term. The maths is identical — multiply the decimal odds of every leg.

Do acca insurance and bonuses change the maths?

They change the settlement, not the underlying probability. A free-bet refund on a one-leg-down acca returns stake in bonus funds, which are worth less than cash because the stake is not returned on the free bet.

Accumulator Calculator

An accumulator rolls each leg's winnings onto the next, so the combined price is the product of every leg. Add your selections below — mark any postponed match as void and the acca re-settles on the remaining legs.

Your accumulator

Stake

Odds format (all)

Currency

Selections (3/20)

Selection 1 name (optional)
Odds
Selection 2 name (optional)
Odds
Selection 3 name (optional)
Odds

Combined decimal odds

6.98

Every active price multiplied together.

Potential payout

€69.83

Stake plus profit if every selection wins.

Potential profit

€59.83

Payout minus your stake.

Combined implied probability

14.32%

1 in 7.0

At least one selection loses

85.68%

The chance this bet does not pay out.

Total selections

Each added selection multiplies the ways this bet can fail.

Drop the riskiest selection

Removing the longest price (2.10) changes the combined odds to 3.32 and lifts the implied chance from 14.32% to 30.08%.

Variance ratingHigh variance

Lower complexityHigh varianceVery high varianceExtreme variance

Every added leg multiplies the ways this bet can fail. Expect long losing runs between wins.

This assumes independent outcomes. Selections from the same match or the same team are correlated, so the real chance can be meaningfully different — usually worse for you than the number above, sometimes better. Bookmaker margin is already inside each price, so the combined implied probability is higher than the true combined chance.

The link contains your selections, so anyone who opens it sees the same calculation. No account and no saved data.

The formulas

Accumulator settlement

combined odds = odds₁ × odds₂ × … × oddsₙ

returns = stake × combined odds

profit = returns − stake

voided leg → treated as 1.00, acca shrinks by one leg

win probability = 1 ÷ combined odds × 100

Acca names and realistic odds

Combined price and win chance with every leg at 1.80 (4/5).
Name	Legs	Combined odds	Win chance	£10 returns
Double	2	3.24	30.86%	£32.40
Treble	3	5.83	17.15%	£58.32
Four-fold	4	10.50	9.53%	£104.98
Five-fold	5	18.90	5.29%	£188.96
Six-fold	6	34.01	2.94%	£340.12
Eight-fold	8	110.20	0.91%	£1,101.99

Common mistakes

Adding a short leg "for safety". A 1.10 leg adds 10% to the price but removes about 9% of your chance of winning. It cannot make the acca safer.
Chasing the bonus. Acca bonuses are a percentage of an already unlikely return, and they never offset the compounded margin.
Assuming void means lost. A void leg reduces the acca; it does not kill it. This calculator handles that case.
Ignoring correlated legs. Two selections from the same match are not independent, so the calculated win chance is only an estimate.

Frequently asked questions

Last reviewed: 24 August 2026. Formulas on this page are checked against the unit test suite that powers every bet.ing calculator.