Round robin calculator:
every combo, every payout.

You pick some legs and a parlay size. The bookmaker builds every possible parlay of that size from your legs, and each one is its own bet. With 4 legs by 2s you get 6 two-leg parlays. Each parlay that wins pays on its own, so you can still get money back when a leg loses.

A parlay is one bet, and every leg must win. A round robin is many smaller parlays made from the same legs. It costs more, because you pay a stake for each parlay, but one losing leg does not wipe out everything.

Six. From 4 legs there are 6 ways to pick 2: AB, AC, AD, BC, BD and CD. At $10 per parlay that costs $60.

It depends on what you want. A round robin costs more than one parlay and pays less when every leg wins. In return, you can still get money back when one leg loses. The bookmaker takes a cut on every parlay inside it, so more parlays means more cut paid. Only bet what you can afford to lose.

It is the size of each parlay. By 2s means every parlay has 2 legs. By 3s means every parlay has 3 legs. Bigger parlays pay more each, but more of your legs need to win.