Parlay and accumulator calculator
Add your selections and the stake. The calculator multiplies the odds and gives you the payout, the profit and the implied probability of the parlay.
What a parlay is
A parlay, also known as an accumulator or acca, joins several selections into one bet. You only collect if all of them win: if one fails, you lose the whole stake. In exchange, the odds multiply together and the potential payout grows very quickly.
The formula
Total odds = odds₁ × odds₂ × … × oddsₙ
Payout = stake × total odds
Profit = payout − stake
Implied probability = 1 ÷ total odds × 100
A worked example
Three selections at 1.80, 1.65 and 2.10, with a €10 stake.
- Total odds: 1.80 × 1.65 × 2.10 = 6.24 (exactly 6.237)
- Payout: €62.37
- Profit: €52.37
- Implied probability: 16.03%
The price looks attractive, but it implies this parlay lands about 16 times out of 100, and that is before counting the bookmaker’s margin.
Why parlays are hard to make profitable
The reason is mathematical: the bookmaker’s margin multiplies too. If each selection carries a margin of about 5%, a three-leg parlay carries a margin of close to 16%, because 1.05 × 1.05 × 1.05 ≈ 1.158. With six selections, it approaches 34%.
In other words, the more legs you add, the more of the expected value the bookmaker keeps. That is why, in many histories, parlays do worse than singles even though they are remembered much more fondly: one big win sticks in the memory while many small losses are forgotten.
Check it with your own data: import your history and compare the yield of your singles with that of your parlays. It is often the most revealing comparison.
Common mistakes
- Looking only at the payout. A €500 payout says nothing without the probability of collecting it.
- Adding the odds. They multiply. Adding them gives a wrong result.
- Thinking “safe” selections cost nothing. A leg at 1.20 looks like a gift, but it still implies 83% at most: roughly one time in six it sinks the parlay.
- Combining related outcomes. Bookmakers usually restrict this because those events are not independent. Where it is allowed, as in “bet builder”, the total price is not a simple multiplication.
- Not accounting for voids. If a selection is voided, the parlay is normally recalculated without it, though this depends on each bookmaker’s rules.
To understand the margin on each selection, use the implied probability calculator. To decide how much to risk in general, read the bankroll management guide. And if you notice you raise your stake after a bad run, take a look at the signs of tilt.
Frequently asked questions
What happens if one selection fails?
You lose the whole bet, unless the bookmaker offers a specific promotion or insurance.
How many selections can I add?
The calculator allows up to 20, although each extra selection lowers the probability of winning and increases the accumulated margin.
Are a parlay and an accumulator the same?
Yes. Parlay is the usual American term; in the UK people say accumulator or acca.
How do I know whether my parlays are profitable?
Separate them in your history and calculate their yield on their own. BetTracker Pro identifies them when importing, so you can filter them and compare them with your singles.