Round Robin Calculator

It is the number of combinations of your selections at the size you picked, written C(n,k). Four selections by 2s is six parlays, five by 2s is ten, six by 2s is fifteen, and five by 3s is ten. A mixed ticket adds the sizes together, so four selections by 2s and by 3s is six doubles plus four trebles, ten parlays in all. Your total stake is the stake per parlay multiplied by that count, which is why a $10 round robin is rarely a $10 bet.

That depends on your prices and the combination size, and it is the figure this page leads with. At four selections of -110 by 2s it is three of four: two correct legs win one parlay out of six and return $36.45 against a $60 outlay. The count always exists and is never worse than every leg landing, because every parlay is priced above 1, so a perfect card always returns more than the ticket cost. Where your prices differ between legs, the page shows two readings: the count at which every card breaks even, and the count at which the best card does.

They are different shapes rather than one being better. At the same total stake the round robin returns something far more often and its best case is much smaller, so it trades ceiling for frequency. On expected value the round robin usually holds less per dollar, because each of its parlays has fewer legs and so carries the bookmaker margin fewer times: four legs shaded 4.5% each cost 8.9% of the outlay taken by 2s and 17.0% taken as one four-leg parlay. Neither figure is positive at real prices, and spreading a losing set of selections across more parlays does not make it a winning bet.

Yes, and it is the most common way the format surprises people. Only the parlays made up entirely of winning selections pay, so a card that is short of perfect pays out on a fraction of the ticket. Six selections by 2s at -110 is fifteen parlays, $150 at $10 each: three correct legs win three of those parlays and return $109.34, and it takes four of the six to get the outlay back. At shorter prices it is worse, and a majority-correct card can lose: five selections at -200 by 2s need four of five, so three correct legs return $67.50 on a $100 ticket. The table on this page prints those rows for your own numbers rather than leaving them to be worked out.

More than this page can show you. Every figure here treats the selections as independent, and round robins are frequently built from legs in the same game, where that is false. Correlated legs land together more often than their prices imply, which makes the middle rows of the table optimistic. The page states the assumption rather than burying it, because the difference is not a rounding detail on a ticket built out of one game.

It does the opposite. A larger size means each parlay needs more of your selections, so more legs have to land before anything pays, and the margin compounds further on each ticket. Taking four selections by 3s rather than by 2s cuts the parlay count from six to four, raises the number of legs needed for a return from two to three, and lowers the expected return per dollar. The smaller sizes are what buy the frequency; the larger ones buy the ceiling.

No, and the shared name is the whole trap. A UK bookmaker's round robin is a fixed 10-bet ticket on exactly 3 selections: 3 doubles, 1 treble, and 3 up-and-down pairs. An up-and-down (Single Stakes About) is not a plain single: it stakes on one selection, and if that selection wins, the original stake, not the return, goes on as a fresh single on the other selection in the pair. A US round robin generalizes to any number of selections and any combination size, with no conditional staking at all. This calculator prices both, as two separate modes, because the same three words describe two different bet slips depending on which side of the Atlantic wrote them.

It guarantees something comes back, but usually not the outlay. The two up-and-down pairs touching a lone winner always pay, because each starts with an unconditional single on that selection. What they do not always cover is what those two pairs risked: a lone winner clears their combined outlay only once its price reaches 3.00. At evens (2.00) it returns half of it. "A winner guarantees a return" is the format's own standard selling line and it is true, so read the figures this calculator prints against the outlay, not against zero.