Enter your legs, choose the combination size and set a stake per bet. The calculator builds every combination at that size and returns the outlay, the all-win figure and what you collect if one leg misses. Three legs combined in doubles produces three bets rather than one treble, which is where the cover comes from.
What a Round Robin Covers
A round robin writes out every combination of a chosen size as its own bet. Three legs combined in doubles gives you three: legs one and two, one and three, two and three. Stake $10 on each and the outlay is $30.
Combining in doubles leaves out both the treble and the singles, so two winning legs is the minimum that pays anything back. What you are buying is partial cover, priced in extra outlay.
A Worked Example
Three legs at decimal odds of 2.00, 1.80 and 1.60, combined in doubles at $10 a bet.
- The three doubles: 2.00 × 1.80 = 3.60, 2.00 × 1.60 = 3.20, 1.80 × 1.60 = 2.88.
- Total outlay: $10 × 3 bets = $30.
- All three legs win: $96.80 returned, a profit of $66.80.
- The 1.60 shot loses: only the 2.00 × 1.80 double survives, returning $36.00 for a profit of $6.00.
- Same three legs as a straight treble, one loser: $0.
How to Read the Results
Two lines carry the decision. The all-win figure of $96.80 shows what a clean sweep is worth. The one-loser line at $36.00 shows what the structure exists for: $6.00 of profit on a Saturday where a treble hands back nothing.
The distance between those two lines is the price of the cover. Three legs landing pays less through three doubles than the same money through one treble, because your stake is split across combinations that cannot all survive. The Parlay Calculator shows what happens with no cover at all.
Combination size is the other lever. Doubles on three legs give three bets; four legs in doubles give six, and the outlay scales with the count rather than the odds. The Trixie Calculator adds the treble back as a fourth bet on the same three legs, and the Patent Calculator puts three singles on top of that.
What the Cover Costs You
A doubles-only round robin pays nothing when just one leg lands. That case comes up more often than most bettors expect, and it is the one the structure does nothing about. Cover starts at two winners.
The premium also gets paid every time it turns out not to be needed. Across a run where all three legs land, three doubles collect less than a treble on the same money would have, and that shortfall is what the insurance cost you.
Then there is the arithmetic on short prices. The example’s doubles run from 2.88 to 3.60, so one surviving double returns $36.00 against a $30 outlay. Combine three legs priced near 1.30 instead and the surviving double comes back below the outlay, which turns the cover into a smaller loss rather than a profit. Run your own prices before assuming two winners means money in hand.
Whichever structure you settle on, the legs still have to be worth backing individually. Gecko Edge generates a win probability for every market from Poisson goal models with a Dixon-Coles correction across 130+ leagues, which is the input that decides whether combining anything makes sense.
Further Reading
- All betting calculators: the full library of 34 free tools
- Staking and bankroll: how should you stake?
- Losing runs and variance: what to expect
What is a round robin bet?
A round robin turns a group of legs into every possible combination of a set size, each placed as a separate bet. Three legs combined in doubles becomes three bets at $10 each for a $30 outlay. Two of the three landing still returns money, where a straight treble on the same legs would return nothing.
How many bets are in a round robin?
It depends on the number of legs and the combination size. Three legs in doubles produces three bets. Four legs in doubles produces six. Add trebles to those same four legs and another four bets join the ticket. Your outlay is the bet count multiplied by the stake per bet, so three doubles at $10 costs $30 rather than $10.
Do I need every leg to win a round robin?
No. A doubles round robin starts paying as soon as two legs land. In the worked example the 2.00 and 1.80 legs winning while the 1.60 loses returns $36.00 against a $30 outlay, a $6.00 profit. One winning leg returns nothing, because every bet in a doubles-only structure needs two names on it.
Is a round robin better value than a treble?
The treble pays more on a clean sweep, and one losing leg wipes it out completely. In the worked example that costs the full $30 while the round robin still returns $36.00. Base the choice on your weakest leg: rate it near a coin-flip and the cover pays for itself, rate all three strongly and the treble keeps more of the upside.