Calculate round robin betting from your inputs, with a result breakdown and worked steps.
Round Robin Betting Formula and Method
Number of tickets = n! / (k! × (n − k)!)
A round robin of size k creates one component parlay for every subset of k legs from the entered list. The cash stake is per component, so total exposure is that stake multiplied by the number of subsets. With three legs and size two, there are three separate two-leg tickets.
How to Use This Calculator
Select the result and any applicable method before entering the visible values. Check the selected record, unit and scoring conventions before calculating. Review the primary result and its breakdown, then open the calculation steps to see how the inputs were used.
Worked Example
With the example inputs in the table, the result is 30 USD. The output prices all subsets; displayed component details are limited to the first 20.
Sum the product-priced return of every size-k subset.
Input and Example Guide
| Input or category | Example or weight | Entry guidance |
|---|---|---|
| Money unit | U.S. dollars (USD) | Choose the convention that applies to your record. |
| Stake per component ticket (selected currency) | 10 | Use the stated unit; retain available precision. |
| Leg prices (decimal odds) | 2, 2, 2 | Use matching entries separated by commas or spaces. |
| Legs per component parlay (count) | 2 | Use a whole count in the stated unit. |
Interpreting the Result
The displayed total return assumes every leg wins and each component pays the product of its leg prices. A loss or void affects several tickets and requires separate settlement. The first twenty component returns are displayed while totals still include all components; the tool permits at most ten starting legs.
The return scenario requires every entered leg to win. Losing or voided legs change multiple component tickets; correlated or promotional pricing may not equal the product of leg odds.
Assumptions and Common Input Errors
The output prices all subsets; displayed component details are limited to the first 20. Keep the same currency and settlement conditions throughout a scenario. Displayed currency amounts are rounded to two decimals; calculations retain precision unless cent allocation is explicitly described.
Saving and Revising a Scenario
A successful calculation is saved in this browser and can be restored on the next visit. Editing an input clears the old result so it is not mistaken for an updated calculation. Reset returns the example inputs and clears the saved result.
Sources
Betfair Help, Decimal Odds and Stake-Inclusive Returns, reviewed 2026. Arithmetic and scenario assumptions are specified above.