Parcae
Glossary · market

Round Robin

A round robin is a wager that automatically generates multiple smaller parlays from a list of selections. Instead of placing one large parlay where all legs must win, you split the bets into every possible combination of a chosen size.

How It Works

You select 4 games and choose a “3-leg round robin.” The book creates 4 separate 3-leg parlays — every possible 3-game combination from your 4 picks:

  • Parlay 1: Games A + B + C
  • Parlay 2: Games A + B + D
  • Parlay 3: Games A + C + D
  • Parlay 4: Games B + C + D

You bet a stake on each one, so a $10 round robin with 4 sub-parlays costs $40 total.

Outcome scenarios:

  • All 4 picks win: All 4 sub-parlays win — maximum payout
  • 3 of 4 picks win: 1 sub-parlay (the one with all 3 winners) wins — partial payout
  • Only 2 of 4 picks win: 0 sub-parlays win — total loss
  • 1 or 0 picks win: 0 sub-parlays win — total loss

Round Robin Formats

Different “size × number of selections” combinations:

  • 3 of 4 (above): 4 sub-parlays of 3 legs each
  • 3 of 5: 10 sub-parlays of 3 legs each
  • 2 of 5: 10 sub-parlays of 2 legs each
  • 4 of 6: 15 sub-parlays of 4 legs each

The combinations grow quickly as you add selections. A 3-of-7 round robin creates 35 sub-parlays.

Why It Matters

Round robins are essentially a way to reduce variance compared to a single big parlay:

With a 4-leg parlay, you need all 4 to win. Lose any one and you lose everything.

With a 3-of-4 round robin, if 3 of 4 win, you still get something back. You don’t need to be perfect.

The trade-off: the math doesn’t actually improve. Each individual sub-parlay still carries the same compounded vig problem as any parlay. You’re just spreading your bet across more wagers, which reduces variance but doesn’t change the fundamentally bad pricing.

Round robins are popular among bettors who want the “thrill” of correlated big-payout potential while reducing the all-or-nothing variance. From a pure +EV perspective, they’re rarely the right choice — but for entertainment-focused bettors, they offer a more forgiving way to play multi-leg structures.

The exception: if you’ve identified specific positively-correlated parlay structures (rare but possible), a round robin lets you capture that correlation across multiple combinations. Most casual round robins, though, are just spreading -EV money across more bets.

For more on parlay math, see Parlays Explained.