This guide demystifies the label "by 2's x3" and explains how round-robin parlays work, step by step. It is written for sports fans and bettors who want a clear, practical explanation of builder labels, the underlying counting math, and how to calculate payouts. You will learn how selections become multiple 2-leg parlays, how to compute each parlay payout using decimal odds, and practical checks to avoid common errors. The aim is to make the concept usable for disciplined bankroll planning.

"By 2's x3" turns three selections into three 2-leg parlays and the builder shows x3 to indicate the count.

Compute each parlay payout by multiplying decimal odds within the pair, then multiply by stake and sum winning parlays.

Round robins reduce variance through partial returns but raise total cost by the number of combinations.

Quick answer: what "by 2's x3" means

"By 2's x3" labels a round-robin bet that turns three selections into three distinct 2-leg parlays, so you get three separate two-team parlays from the same set of picks. Each 2-leg parlay only pays if both legs win, and any winning parlays produce additive returns rather than an all-or-nothing result, which is how round robins differ from one single multi-leg parlay Investopedia round-robin definition.

How does "by 2's x3" actually work and how do I calculate payouts?

It means three distinct two-leg parlays are created from three selections; convert odds to decimal, multiply within each pair, apply your stake-per-parlay, and sum any winning parlays to find total return.

On a bet slip or builder you will typically see the shorthand "by 2's" plus a multiplier such as "x3"; the multiplier is the count of distinct 2-leg parlays produced from your selection list and it determines how many separate stakes you place FanDuel research on round robin labels. For more operational detail see the FanDuel support page What is a Round Robin - FanDuel Support.

How round robin bets work in practice

Builder labels and the multiplier

A round-robin bet builder splits your list of selections into all smaller parlays at the chosen sub-parlay size. When you pick "by 2's" the builder generates every unique pair of selections and shows the number of such pairs as the "x#" multiplier, which is also used to calculate total cost TheLines round robin explanation.

From selections to parlays: the process

In practice you choose selections, set the stake-per-parlay, and the builder previews each 2-leg parlay with its potential payout. The displayed multiplier equals the number of parlays and the total stake equals stake-per-parlay times that multiplier, so the builder both explains and automates the math FanDuel research on round robin labels. (See our blog overview at Funded Plays blog.)

The counting logic: combinations behind "by 2's"

The combination formula C(n,2)

To count how many 2-leg parlays a list of n selections produces, use the combinations formula C(n,2) = n(n-1)/2. The formula gives the number of unique unordered pairs you can form from n items and is the standard combinatorics result used by builders and explainers Wikipedia on combinations.

Explore round-robin scenarios with the Funding Plays challenge mindset

Try the worked examples below with your own numbers or a calculator to see how the multiplier, stake-per-parlay, and payouts interact.

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Quick examples with n = 3, 4 and 5 selections

With n = 3 you get C(3,2) = 3, which explains the "x3" label for a by 2's bet on three selections. For n = 4 you get C(4,2) = 6 pairs, and for n = 5 you get C(5,2) = 10 pairs. These counts drive the total number of 2-leg parlays and therefore the overall cost of the round robin Wikipedia on combinations.

How payout math works for each 2-leg parlay

Converting odds to decimal

Start by converting each selection's odds to decimal format; decimal odds let you multiply leg prices directly. Most industry explainers and bookmakers show the decimal conversion rules and recommend using decimal odds for parlay math Pinnacle on converting and using decimal odds.

Multiplying within each parlay and computing profit

For a two-leg parlay the payout equals stake × (decimal odd A × decimal odd B). Profit equals payout minus the stake. Each 2-leg parlay only returns money when both legs in that parlay win, and in a round robin you add up the payouts from any winning parlays to get your total return Investopedia round-robin definition.

Step-by-step example: calculate a by 2's x3 with sample odds

Choose three sample selections

Pick three hypothetical selections and convert them to decimal odds. For example, use decimal odds like 1.80, 2.10, and 1.60 to keep the arithmetic clear; convert American or fractional odds to these decimal values first if necessary Pinnacle on parlay calculation steps.

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Compute three 2-leg parlay payouts and total return

Number the parlays produced by the three selections: pair A-B, pair A-C, and pair B-C. For each pair multiply the two decimal odds, then multiply by your stake-per-parlay to get that parlay's payout; repeat for all three and sum any winning parlays to find total return. The builder's "x3" matches these three combinations and the total cost equals stake-per-parlay times three FanDuel research on round robin examples.

Minimalist 2D vector three step diagram showing American odds to decimal conversion then multiplying decimals and payout for round robin sports betting

Cost and bankroll planning for round robins

Total stake calculation

Total cost is simple arithmetic: stake-per-parlay multiplied by the number of parlays equals your outlay. For a by 2's x3 that means total cost = stake-per-parlay × 3, and that same calculation scales when the builder produces more combinations TheLines on round robin cost. You can also check round-robin payouts using a calculator such as the round robin calculator at AceOdds round robin calculator.

How round robins change bankroll exposure

Round robins increase the number of individual wagers you place compared with a single combined parlay, so you should set stake-per-parlay with that multiplier in mind to control total exposure and preserve bankroll discipline Action Network round robin guide. For Funded Plays details on bankroll approaches see Funded Plays.

When a round robin is a smart choice

Situations that favor partial payouts

Round robins often make sense when you like several selections but are unsure all will land; the structure lets some correct pairs still return money, reducing variance compared with a single long parlay Action Network on variance and partial returns.

Compute total payout for a by 2's round-robin with three selections

Enter decimal odds for selections and stake in the same currency

When to prefer single parlays instead

Choose a single parlay when you want a higher upside from all legs winning and you are comfortable with the all-or-nothing outcome; remember that round robins trade higher upfront cost for lower variance and more frequent partial returns TheLines on choosing bet types. See the Fox Sports primer for another overview Fox Sports round robin article.

Common mistakes and how to avoid them

Counting and cost errors

The most common errors are miscounting combinations or forgetting to multiply stake by the number of parlays. Always verify the builder's "x#" and check that total cost equals stake-per-parlay times the multiplier before submitting a ticket FanDuel guidance on builder previews.

Odds and conversion errors

Avoid using American or fractional odds in parlay multiplication without converting to decimal first; incorrect conversion produces wrong payouts, so double-check conversion formulas or use a calculator that accepts different formats Pinnacle on converting odds.

Using a calculator or the sportsbook builder to check returns

What to enter into a round-robin calculator

Enter your selections, their decimal odds, the parlay size (by 2's), and the stake-per-parlay. A calculator or builder will list each 2-leg parlay, show per-parlay payouts, and give the total cost and total potential return TheLines on using builders.

Interpreting the calculator output

Confirm the calculator output matches the builder's multiplier and preview: every listed parlay should reflect the multiplication of its two decimal odds times your stake, and the sum of payouts for winning pairs gives the real return in a round robin Pinnacle on reading parlay outputs. Additional calculators and tools are linked in our blog post on evaluations.

Variants: by 2's compared with by 3's and larger sets

How the chosen parlay size changes the multiplier

The multiplier follows the general formula C(n,k) for combinations, so moving from by 2's to by 3's reduces the number of sub-parlays for the same n in many cases and changes the cost and payout profile according to the new combination count Wikipedia on combinations.

When to use larger sub-parlays

Use larger sub-parlays when you prefer higher per-parlay payouts and fewer total combinations, but remember that each larger sub-parlay requires more legs to win, which raises the probability threshold for any single sub-parlay to pay Action Network on choosing sub-parlay size.

How round robins affect risk and variance

Why round robins reduce variance

Because round robins break a selection set into many smaller parlays, they allow some correct pairs to return money even if others lose, which reduces the variance of outcomes relative to a single long parlay Action Network on variance.

The trade-off: higher cost for lower variance

The trade-off is straightforward: you pay for multiple parlays, which raises total stake, in exchange for more chances at partial returns. Compare expected value per dollar when deciding which structure better fits your plan TheLines on trade-offs.

Pre-place checklist for a by 2's x3 round-robin

Five quick checks before submitting

1) Verify the builder shows "x3" for three selections. 2) Confirm total cost equals stake-per-parlay times 3. 3) Double-check odds are in decimal format or correctly converted. 4) Look for correlated outcomes that could invalidate independent pair benefits. 5) Ensure stake-per-parlay fits your bankroll rules FanDuel on preplace checks.

Confirming builder output

Use the builder preview or a calculator to list each 2-leg parlay and its payout and to verify the multiplier and total stake before confirming the bet TheLines on verifying builder output.

Glossary: short definitions of key terms

Parlay, leg, decimal odds

Parlay: a combined bet that pays only when all included legs win. Leg: a single selection inside a parlay. Decimal odds: the multiplier used to compute payout per stake and the preferred format for multiplying legs in a parlay Pinnacle on decimal odds.

Combination formula and multiplier

Combination: the count of unique groups from a set. Multiplier: the builder's displayed count of sub-parlays, derived from combination formulas such as C(n,2) for by 2's Wikipedia on combinations.

Bottom line: using "by 2's x3" well

Short summary

"By 2's x3" from three selections creates three 2-leg parlays; the builder shows x3 and total cost equals stake-per-parlay times 3. Payouts depend on which pairs win, and round robins trade higher total cost for reduced variance and more chances at partial returns Investopedia round-robin definition.

Responsible-use reminder

There are no guaranteed returns. Control stake-per-parlay to protect your bankroll, verify builder previews, and use calculators to check expected payouts before placing a round-robin structure Action Network on responsible use.

What exactly does "by 2's x3" mean?

It means three selections are turned into three distinct 2-leg parlays; each two-leg parlay only pays if both legs win and total cost equals stake-per-parlay times three.

How do I calculate a parlay payout in a round robin?

Convert each leg to decimal odds, multiply the decimal odds inside each 2-leg parlay, multiply by the stake for that parlay, and sum any winning parlay payouts.

Should I use a round robin or a single parlay?

Use a round robin when you favor lower variance and partial returns; choose a single parlay when you want a larger payout only if every leg wins.

If you use a builder or calculator, always verify the multiplier and total cost before placing a round robin. Keep stakes conservative and treat round robins as a tool for managing variance rather than a shortcut to guaranteed returns.