Round Robin Calculator
Pick your selections and a combination size. This builds every sub-parlay, prices it, and totals what the ticket actually costs.
2 to 4
Total risked
$60.00
6 separate 2-leg parlays at $10.00 each. This is a 6-bet ticket, not one bet — the "round robin" label hides how much money is going down.
- Combinations
- 6
- Stake per combination
- $10.00
- Return if everything wins
- $218.68
- Best case profit
- +$158.68
- Marked winners return
- —
C(4,2)
Tick winners below to settle the ticket.
Mark winners
| Legs | Combined | American | Returns | Result |
|---|---|---|---|---|
| Selection 1 + Selection 2 | 3.645 | +264 | $36.45 | — |
| Selection 1 + Selection 3 | 3.645 | +264 | $36.45 | — |
| Selection 1 + Selection 4 | 3.645 | +264 | $36.45 | — |
| Selection 2 + Selection 3 | 3.645 | +264 | $36.45 | — |
| Selection 2 + Selection 4 | 3.645 | +264 | $36.45 | — |
| Selection 3 + Selection 4 | 3.645 | +264 | $36.45 | — |
A round robin is not a way to reduce parlay risk — it is a way to place a lot of parlays at once. Every combination still pays the parlay margin, so the ticket as a whole carries more of the book’s hold than the same money on straight bets. Pushes and voided legs are not modelled here; books re-price the affected parlays and the rules vary.
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What is a round robin bet?
A round robin takes a group of selections and turns them into every possible parlay of a chosen size. Four selections by twos becomes six two-leg parlays, each a separate bet with its own stake.
The appeal is that you no longer need everything to land — with four picks by twos, three winners still pays three of your six tickets. That softens the outcome compared with one all-or-nothing parlay.
What the name hides is the cost. Six selections by threes is twenty bets, so someone who thought they were placing a $10 wager has staked $200. Every combination still carries the parlay margin.
How it works
A round robin takes a group of selections and turns them into every possible parlay of a chosen size. Four selections by twos is six two-leg parlays; five by threes is ten three-leggers. Each combination is a separate bet with its own stake, which is the part the name obscures.
The count is the binomial coefficient — n choose k — and it grows faster than people expect. Six selections by threes is twenty bets. At $10 each that is a $200 ticket, and someone who thought they were placing a $10 bet has placed twenty times what they intended. Watching the total risked figure move as you change the combination size is the single most useful thing this calculator does.
The appeal is that you no longer need everything to land. With four selections by twos, three winners still pays three of your six parlays. That softens the outcome, and it is genuinely why people use round robins — but it is softening, not protection. Every combination is still a parlay, and every parlay still carries the book’s margin compounded across its legs. Spreading the money over more parlays spreads the margin over more parlays too.
The outcome checker settles by combination, not by winner count. That distinction matters as soon as your legs are priced differently: with four selections at wildly different prices, “three of four won” can pay very different amounts depending on which three. Only combinations where every leg won pay anything, and that is what the table shows.
The formula
number of bets = C(n,k) = n! / (k!(n−k)!) 4 by 2s → 6 bets 5 by 3s → 10 bets 6 by 3s → 20 bets 8 by 4s → 70 bets combination price = Π decimalⱼ over its k legs combination payout = stake per combo × combination price total risked = C(n,k) × stake per combination settled = Σ payout over combinations where EVERY leg won
Each combination is an independent parlay. Its price is the product of its legs, exactly as in the parlay calculator.
A worked example
Four selections at −110 each, by twos, at $10 a combination. That is C(4,2) = 6 parlays and $60 at risk.
Each two-leg parlay at −110/−110 is 1.909 × 1.909 = 3.645, so a winning combination returns $36.45. If everything lands, all six pay: $218.68 back on $60, a profit of $158.68.
Three winners is the interesting case. Three of the four selections appear together in exactly three of the six pairs, so three combinations pay $36.45 each — $109.34 against $60 risked, a profit of $49.34. Two winners pays exactly one combination: $36.45 back on $60, a $23.55 loss. So the ticket needs three of four just to make a modest profit.
Common questions
- How many bets am I actually placing?
- C(n,k) of them, each at your stake per combination. Four by twos is six bets; six by threes is twenty. Multiply by the per-combination stake before you confirm — the total is usually much larger than people intend.
- Is a round robin safer than a parlay?
- It has a softer distribution — you can lose a leg and still collect something — but it is not cheaper. Every combination pays the parlay margin, so more combinations means more total margin paid on the same opinions.
- How many legs do I need to win to break even?
- It depends on the prices, which is why the settle-by-marking-winners feature exists. As a rough guide, at even-money-ish legs you usually need to lose no more than one selection before the ticket goes negative.
- What happens if a leg pushes?
- Books re-price every parlay containing it, usually by dropping the leg and settling at the reduced price. The rules vary between books, so pushes are deliberately not modelled here rather than modelled wrongly.
- Why not just bet the selections straight?
- Often you should. Straight bets pay one margin instead of compounding it across every combination. Round robins buy a longer payout distribution, and that costs expected value — the parlay-vs-straight calculator puts the two side by side.
The guide behind this calculator
Related calculators
- Parlay CalculatorCombine up to twenty legs, toggle any of them off, and price the ticket.
- Parlay vs StraightThe same selections combined against the same selections separately.
- Bet Payout CalculatorProfit, total return and the win rate a price needs to break even.
- Teaser CalculatorWhat a teaser pays, and the per-leg win rate it needs.
For informational and analytical purposes only. These tools do not predict outcomes and do not recommend wagers.