Key takeaways
- An accumulator, or parlay, links several selections into one bet and pays only if every one wins.
- The decimal odds of each leg multiply, so the potential return climbs fast.
- The bookmaker margin compounds with every leg, which is why accumulators are the most profitable bet type for bookmakers.
- Permutation bets such as a Trixie or Lucky 15 split your stake across several bets, so a few winners can still pay out.
Accumulators are the most popular bet in UK football betting and the parlay is a staple of every US sportsbook. The appeal is obvious: a small stake can turn into a large return. The catch is just as clear, because one wrong leg ends the whole bet.
This guide explains how they work, shows the maths, and covers the permutation bets that give you a safety net.
What is an accumulator?
An accumulator combines two or more selections into a single bet. If every selection wins, you are paid at the combined odds. If any one loses, the entire bet loses. Your winnings from the first leg roll onto the second, then the third and so on, which is why they are sometimes called multiples.
Common names by number of selections:
- Double: 2 selections
- Treble: 3 selections
- 4-fold, 5-fold and so on: 4, 5 or more selections
In the US the same bet is a parlay, and a two-leg version is a two-team parlay. A parlay built from markets in one game is a same-game parlay, covered in our bet builder guide.
How accumulator odds are calculated
Multiply the decimal odds of every leg. The calculation is the same whatever format you see on the betting slip, so convert first if you need to. The odds converter will do it, and the parlay calculator multiplies a full slip for you.
Worked example: a four-fold
You back four selections with a 10 stake:
| Leg | Fractional | Decimal | American |
|---|---|---|---|
| Team A to win | 1/2 | 1.50 | -200 |
| Team B to win | Evens | 2.00 | +100 |
| Team C to win | 6/4 | 2.50 | +150 |
| Team D to win | 4/5 | 1.80 | -125 |
Combined decimal odds = 1.50 x 2.00 x 2.50 x 1.80 = 13.50.
- Total return = 10 x 13.50 = 135
- Profit = 135 - 10 = 125
- In fractional that is 25/2 (12.5 to 1), and in American it is +1250.
The implied probability of all four winning is 1 / 13.50 = 7.4%. Multiply the leg chances together to check: 66.7% x 50% x 40% x 55.6% is also about 7.4%.
The same maths applies in American odds. A three-leg parlay at -110 per leg has decimal odds of 1.909 x 1.909 x 1.909 = 6.958, so a $10 stake returns about $69.58, which is a profit of $59.58 or roughly +596.
Why accumulators are hard to win
Probability multiplies as well as odds. If you believe each of four selections has a 60% chance of winning, the chance that all four win is 0.60 x 0.60 x 0.60 x 0.60 = 0.1296, or about 13.0%. Four selections that each look “likely” combine into something that loses almost 87 times out of 100.
Then the margin joins in. Every price has a bookmaker margin inside it, and on an accumulator that margin applies to each leg in turn. If each of four legs carries a 5% margin, the combined margin is roughly 1.05 to the power of 4, or about 21.6%. Compare that with the 4.8% to 5% margin on a single match result and you can see why bookmakers promote accumulators so heavily. For more on this, see how betting odds work.
Permutation bets: a safety net
A full-cover bet places several bets from your selections at once, so you are not wiped out by one loser. The cost is that your stake is split across many bets and the total stake is the unit stake times the number of bets.
| Bet | Selections | Number of bets | Made up of |
|---|---|---|---|
| Trixie | 3 | 4 | 3 doubles, 1 treble |
| Patent | 3 | 7 | 3 singles, 3 doubles, 1 treble |
| Yankee | 4 | 11 | 6 doubles, 4 trebles, 1 four-fold |
| Lucky 15 | 4 | 15 | 4 singles, 6 doubles, 4 trebles, 1 four-fold |
| Canadian (Super Yankee) | 5 | 26 | 10 doubles, 10 trebles, 5 four-folds, 1 five-fold |
| Heinz | 6 | 57 | 15 doubles, 20 trebles, 15 four-folds, 6 five-folds, 1 six-fold |
| Goliath | 8 | 247 | 28 doubles, 56 trebles, 70 four-folds, 56 five-folds, 28 six-folds, 8 seven-folds, 1 eight-fold |
Worked example: a Trixie at 5 a bet
You pick three selections at 2.00, 3.00 and 4.00 and place a Trixie at 5 per bet. A Trixie is 4 bets, so the total stake is 4 x 5 = 20.
Scenario 1: only the 2.00 and 3.00 selections win. Only the double of those two wins: 2.00 x 3.00 = 6.00, so the return is 5 x 6.00 = 30. Profit = 30 - 20 = 10. A plain treble would have lost everything.
Scenario 2: all three win.
- Double 2.00 x 3.00 = 6.00
- Double 2.00 x 4.00 = 8.00
- Double 3.00 x 4.00 = 12.00
- Treble 2.00 x 3.00 x 4.00 = 24.00
Total odds across the four bets = 50.00, so the return is 5 x 50.00 = 250. Profit = 250 - 20 = 230.
The trade-off is plain. With a Trixie, a 20 outlay on three selections gets you more ways to be paid, but a smaller top prize than a 20 treble, which would return 20 x 24.00 = 480 if all three won.
How to build a sensible accumulator
- 1
Keep it short
Every extra leg lowers your chance of winning and raises the margin you pay. Two to four selections is a sensible range.
- 2
Pick selections you have a view on
Do not pad a slip with obvious favourites at 1.10 just to inflate the odds. Short prices add little return and still add risk.
- 3
Check each price across bookmakers
A tiny improvement on each leg multiplies across the slip. Compare at licensed operators on our betting sites pages.
- 4
Decide the stake first
Choose a stake you can comfortably lose, then see what the odds pay. Never work backwards from a target win.
- 5
Use the calculator
Run the slip through the parlay calculator to see return, profit and the chance of every leg landing.
Rules to check before you bet
- Void legs: a postponed or abandoned match usually voids that selection, and the odds drop out of the multiple.
- Dead heats: in a dead heat, the stake on that leg is divided by the number of tied participants, which cuts the return.
- Same-event restrictions: bookmakers often refuse to combine selections that are linked, such as a team to win and its striker to score. The same-game version is a separate product.
- Payout limits: most operators cap the maximum winnings on a single bet.
- Minimum leg odds on promotions: boosted accumulators often require each leg to be 1.30 or longer.
Bet only through licensed betting sites, and set deposit limits before you start. Our responsible gambling page lists tools and support.
Frequently asked questions
What is the difference between an accumulator and a parlay?
Nothing in how they work. Accumulator is the UK and Irish term, parlay is the American one. Both multiply the odds of every selection, and every leg must win.
How many selections can I put in an accumulator?
A double has two and a treble three, with no standard upper limit. Bookmakers set their own maximums and payout caps, so check the terms before you build a long one.
What happens if one selection is void?
The void leg is removed and the bet is recalculated on the remaining selections, with that leg treated as odds of 1.00. A treble with one void leg becomes a double.
What is the difference between an accumulator and a Lucky 15?
An accumulator is one bet that needs every leg to win. A Lucky 15 is 15 separate bets on four selections, so you can still be paid if only one of them wins.
Are accumulators bad value?
They usually are over the long run. The bookmaker margin applies to every leg and compounds as you add selections, so the effective margin grows with each leg.
Can I cash out an accumulator?
Many licensed bookmakers offer cash out on accumulators, but the offer is priced below fair value and may be unavailable if a market is suspended.
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About the author
Daniel WardFounder and Editor
Daniel Ward founded BettingSeeker and is responsible for everything published on it. He has spent his career in SEO and content for online betting and casino comparison sites, and today leads SEO for a portfolio of gambling comparison sites across several countries.
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