Four picks go into a straight parlay, one leg loses, and the ticket pays nothing even though three of four picks were right. A round robin splits that same list of picks into every smaller parlay it can build, so one loser trims the payout instead of wiping it out.
Enter a stake, pick a parlay size, and list the odds for each selection. The calculator returns how many parlays that combination creates, the total amount at risk, and what the ticket pays if every pick wins, if one loses, or if two lose, so the cost and the downside are both known before the bet goes in.
Start with the stake per parlay, which is the amount risked on each individual combination the round robin builds, not the total wagered. Next choose the parlay size: by 2s, by 3s, or by 4s, which sets how many legs go into each parlay pulled from the picks list.
Then enter the picks themselves, from 3 up to 8, each with its own odds. The calculator reads the result off three numbers: how many parlays the picks produce, the total risk (stake times the number of parlays), and a payout for each losing scenario, from every pick winning down to two or more losing.
A round robin works off a simple count: with n picks taken k at a time, the number of parlays is n choose k. Each of those parlays pays the stake times the product of its own legs’ decimal odds. If some picks lose, only the parlays that avoided every losing pick still cash, and the total risk is just the number of parlays times the stake.
The worked example uses four picks at -110 each, a $10 stake per parlay, and parlay size 2. Four picks taken two at a time makes 6 parlays, so total risk is 6 times $10, or $60.00. If all four picks win, every parlay cashes and the ticket profits $158.68. If one pick loses, only the parlays that excluded that pick still pay, leaving $49.34. If two picks lose, the surviving parlays no longer cover the stake, and the result is -$23.55.
A round robin matters most when a bettor likes several picks but doesn’t trust all of them equally, and wants one wrong leg to cost money rather than kill the entire ticket. That’s the whole point: turn a list of picks into every parlay of a chosen size, so a single loser only removes the parlays that contained it.
The common mistake is treating the stake per parlay as the total cost. With 4 picks by 2s, that $10 stake becomes $60 in total risk across 6 parlays, and bettors who miss that step end up risking far more than they meant to.
A sharp bettor checks the total risk first, then looks at the one-loss and two-loss numbers before placing the ticket. If the payout after one loss doesn’t come close to covering the stake, the round robin isn’t doing its job and a smaller parlay size or fewer picks usually fits better.
What is a round robin bet? It’s a single stake per parlay applied across every smaller parlay a list of picks can form, so picks are combined in groups instead of riding on one all-or-nothing parlay.
How much does a round robin actually cost? Total risk is the stake per parlay multiplied by the number of parlays the picks produce, not the stake alone. Four picks by 2s makes 6 parlays, so a $10 stake per parlay means $60 at risk, not $10.
Is a round robin better than one big parlay? It depends on what the bettor wants. A straight parlay pays more if everything wins but pays zero on a single loss. A round robin pays less on a full sweep but still returns money, like $49.34, when one pick out of four misses.
What happens if half the picks lose? Only the parlays made entirely of winning picks still pay out. In the four-pick, by-2s example, two losing picks leave only one parlay untouched, and that isn’t enough to cover the stake, which is why the result turns negative at -$23.55.