Round robin parlay calculator: how it works + worked examples
A round robin turns a handful of picks into every smaller parlay combination. Here is exactly what the calculator is doing to your stake, worked twice, with the break-even math attached.
Run your own numbers
Enter your legs and per-ticket stake in the free round robin calculator — it prices every combination and shows total risk before you bet.
What a round robin actually is
A round robin is a batch of parlays, not a bet type of its own. You pick n selections and a combination size k, and the book writes one parlay for every possible group of k legs. Your stake applies to each ticket, so total risk is stake × number of tickets.
The number of tickets is the binomial coefficient C(n, k) = n! / (k! × (n − k)!). The calculator's real job is bookkeeping: convert each American price to decimal, multiply the legs inside each ticket, apply your stake, and add up what happens at every count of winners.
To convert prices by hand first, the odds converter does American → decimal → implied probability in one step.
Worked example 1 — 3 teams, by 2s, $10 per ticket
Three legs at −110 (decimal 1.909 each). C(3,2) = 3 tickets, so $30 total risk.
| Ticket | Decimal | Stake | Return if it hits |
|---|---|---|---|
| A + B | 3.645 | $10 | $36.45 |
| A + C | 3.645 | $10 | $36.45 |
| B + C | 3.645 | $10 | $36.45 |
- 3 winners: all three tickets cash — $109.35 back on $30 risked, a profit of $79.35.
- 2 winners: exactly one ticket cashes — $36.45 back on $30, a profit of $6.45. A straight 3-leg parlay would have lost the whole stake here.
- 1 or 0 winners: nothing cashes — you lose $30.
That "2 of 3 still profits" line is the entire appeal, and it costs you the difference between $79.35 and the $66.14 a $30 straight parlay would have paid on a clean sweep.
Worked example 2 — 4 teams, by 3s, $5 per ticket
Four legs, mixed prices: −110 (1.909), −120 (1.833), +100 (2.000), +150 (2.500). C(4,3) = 4 tickets, so $20 total risk.
| Ticket | Decimal | Return if it hits |
|---|---|---|
| −110 + −120 + +100 | 7.000 | $35.00 |
| −110 + −120 + +150 | 8.750 | $43.75 |
| −110 + +100 + +150 | 9.545 | $47.73 |
| −120 + +100 + +150 | 9.165 | $45.83 |
- 4 winners: every ticket cashes — $172.31 back on $20, a profit of $152.31.
- 3 winners: exactly one ticket cashes, and which one matters. Losing the +150 leg returns $35.00 (+$15.00); losing the −110 leg returns $45.83 (+$25.83).
- 2 or fewer winners: every ticket needs three legs, so nothing cashes — you lose $20.
The part most round robin guides skip
A round robin does not remove vig — it multiplies it. Each leg at −110 carries roughly 4.5% hold, and every ticket compounds that hold across its legs. Spreading the money over combinations smooths your results; it does not change the sign of your expected value.
So the only question worth asking is whether the legs are priced better than fair. Strip the juice on each leg with the no-vig calculator, and read how +EV betting works before you commit a bankroll to combinations.
If you want the legs picked for you from prices that already clear the fair-value bar, the free AI parlay generator only stacks vetted +EV plays, and the Kelly calculator will tell you how small the stake should really be.
FAQ
What does a round robin parlay calculator do?
It expands your picks into every smaller parlay combination, prices each one from the American odds you entered, and totals the stake, the payout for each number of winners, and your break-even hit rate. It is the same multiplication a parlay calculator does, run once per combination.
How many parlays does a round robin create?
It is the binomial coefficient C(n, k): the number of ways to choose k legs from n picks. A 3-team round robin by 2s is C(3,2) = 3 parlays. A 4-team by 3s is C(4,3) = 4 parlays. A 5-team by 2s is C(5,2) = 10 parlays.
Is a round robin better than a straight parlay?
It is lower variance, not higher expected value. Splitting the same money over combinations means one loss no longer voids everything, but every ticket still carries the book's vig. If your legs are negative expected value, so is the round robin.
How should I size a round robin?
Set your total risk first, then divide by the number of combinations, because the calculator multiplies your per-ticket stake by every combination. A $10 stake on a 5-team by-2s round robin is $100 at risk, not $10.