Calculate a round robin bet’s total stake, number of parlays and potential payout from American or decimal odds, your stake per parlay and parlay size.
Round Robin Betting Formula and Method
Number of tickets = n! / (k! × (n − k)!)
This calculator uses round robin to mean all size-k parlay subsets, rather than conditional or any-to-come wagers sometimes called a UK round robin. 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
Enter a USD stake per component, 2–10 decimal leg prices and the whole number of legs per component parlay. Select Calculate. Open Calculation details for the subset method and the first 20 component returns.
Worked Example
For three distinct legs each at decimal odds 2 and size two, there are three component parlays. At $10 per component, total stake is $30. If all legs win, each component returns $40, for $120 gross return and $90 net profit.
Sum the product-priced return of every size-k subset.
Input and Example Guide
| Input or category | Example or weight | Entry guidance |
|---|---|---|
| Money unit | U.S. dollars (USD) | All cash values use USD; no currency conversion is performed. |
| Stake per component ticket ($) | 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. Stake accepts exact cents and decimal leg prices accept up to six places. Unrounded component returns are summed before half-up rounding the total to cents; individually rounded component returns may not sum to the rounded total. Actual bookmaker rounding or limits may differ.
Saving and Revising a Scenario
A successful calculation is saved in this browser and can be restored on the next visit. Editing inputs retains the previous result with a clear update warning. Select Calculate to update it. Reset clears this calculator’s fields, result and saved state.
Sources
Betfair Help, Decimal Odds and Stake-Inclusive Returns, reviewed 2026. Arithmetic and scenario assumptions are specified above.
