Round Robin
Round Robin Calculator: By 2s, By 3s, Full Cover Cost and One-Loss Payout
The round robin calculator breaks 3 or more picks into every parlay of the sizes you choose and shows the number of parlays, total cost, maximum payout and what you collect if one leg loses. On FanDuel or DraftKings, 3 picks 'by 2s' means three two-leg parlays, and the stake applies to each one: $5 by 2s on 3 picks costs $15. 'By 2s and 3s' adds the three-leg parlay; full cover buys every size, singles included.
Round Robin Calculator
Round RobinBy 2s, by 3s or full cover: total cost, max payout and what one loss pays
Parlays = Σ C(N, k) for every parlay size k you select; total cost = parlays × stake per parlayEach parlay pays stake × the product of its leg odds; only parlays with every leg winning pay.
How to use the round robin calculator
Enter 3 to 8 picks with their odds, then select the parlay sizes. With 4 picks, choosing by 3s and by 4s gives C(4,3) + C(4,4) = 4 + 1 = 5 parlays; choosing every size from singles up is full cover, 15 parlays. The quick presets fill in the common combinations.
The stake applies to each parlay, exactly as on the FanDuel and DraftKings bet slips: 5 parlays at $30 each cost $150 in total. Check the total before you confirm, because a full cover on 5 picks runs 31 parlays and the ticket cost climbs fast.
The most useful output is the payout with one loss. On 4 picks by 3s and 4s, if the pick with the highest odds loses, one three-leg parlay still pays; if the shortest price loses, the surviving parlay pays the least. Those two numbers show how much protection the round robin actually gives.
By 2s, by 3s and full cover: what the labels mean
'By 2s' means every two-leg parlay from your picks, 'by 3s' every three-leg parlay, and so on. On 3 picks, by 2s is 3 parlays; adding by 3s makes 4; full cover adds the 3 singles for 7. On 4 picks, by 3s and 4s is 5 parlays; by 2s, 3s and 4s is 11; full cover is 15. On 5 picks, by 2s through 5s is 26 parlays and full cover is 31.
US sportsbooks list these options on the bet slip once you have 3 or more picks. This calculator lets you combine any sizes and set one stake per parlay, which matches how the slip prices the ticket.
Round robin cost versus protection: how to choose
More parlay sizes mean more protection but a bigger outlay, and the small parlays pay little. The singles inside a 4-pick full cover are just four straight bets, and a winning single at +60 (1.6) to -111 (1.9) earns a few dollars. A common mistake is buying full cover for the one-loss protection, then finding the many small parlays drag down the return when everything wins.
A more practical approach: when you like all your picks, use the larger sizes (by 3s and 4s on 4 picks, by 4s and 5s on 5); when one or two picks are shaky, drop them and build a smaller ticket instead of paying for full cover to insure the doubtful legs.
Example: 4 picks by 3s and 4s at +60 (1.6), +70 (1.7), +80 (1.8), -111 (1.9), $30 per parlay
- Parlays = C(4,3) + C(4,4) = 4 + 1 = 5; total cost = 5 × $30 = $150.
- All four win: the four-leg parlay pays $30 × 1.6 × 1.7 × 1.8 × 1.9 = $279.07; the four three-leg parlays pay $30 × (1.7×1.8×1.9 + 1.6×1.8×1.9 + 1.6×1.7×1.9 + 1.6×1.7×1.8) = $30 × (5.814 + 5.472 + 5.168 + 4.896) = $640.50; total about $920, profit about $770.
- One loss (the -111 pick misses): only the 1.6 × 1.7 × 1.8 parlay survives, paying $30 × 4.896 = $146.88 on a $150 ticket, a $3 loss. If the +60 pick misses instead, the 1.7 × 1.8 × 1.9 parlay pays $174, a $24 profit.
The one-loss 'protection' on a by 3s and 4s round robin is roughly break-even, not profit. The real return comes from going 4 for 4, so this structure suits bettors who like all four picks and want a small hedge against one miss.
FAQ
What does a round robin by 3s mean?+
By 3s means every three-leg parlay you can build from your picks, each at the same stake. On 4 picks that is 4 parlays; add by 4s and the four-leg parlay makes 5. Any 3 winners pay one parlay; 4 for 4 pays all five.
What is the difference between by 2s+3s and full cover on 3 picks?+
By 2s and 3s on 3 picks is three two-leg parlays plus one three-leg parlay, 4 tickets. Full cover adds the 3 singles for 7. Full cover survives more losses, but the three extra singles pay very little.
Does a round robin still pay if one pick loses?+
Yes, as long as at least one parlay in the round robin has every leg winning. On 4 picks by 3s and 4s at +60 (1.6) to -111 (1.9), the one-loss payout is roughly the ticket cost, so it lands near break-even depending on which pick misses.
How do I place a round robin at a US sportsbook?+
Add 3 or more picks to your bet slip and open the round robin options, labeled by 2s, by 3s and so on. Select the sizes you want and enter the stake per parlay; the slip multiplies it by the number of parlays to show the total cost.
Is a round robin the same as a system bet?+
Yes. 'System bet' is the term European sportsbooks use for the same structure. US books call it a round robin and label the sizes by 2s, by 3s, by 4s. The math is identical: add up the number of parlays of each size you select.
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