Three powerful calculators in one place — ROI projection, parlay odds, and round robin builder. All free to use.
Break-even win rate: At -110 you need 52.4% to break even. Every point above that is profit.
ROI: Return on Investment as % of total wagered. Professionals target 5–12% long-term.
Compounding: Resizing your unit as your bankroll grows accelerates profits significantly over time.
Enter American odds for each leg. Check the box if a leg has already won (for live tracking). Add up to 12 legs.
Parlays multiply the decimal odds of each leg together. A 3-team parlay at -110/-110/-110 pays roughly +596 — but all three legs must win.
True odds vs. book odds: Books pay slightly less than true odds on most parlays, keeping a 20–30% edge. The house edge compounds with each leg added.
Correlated parlays can offer value — combining a team win with their QB's passing yards over, for example, increases the true probability vs. what the book assumes.
A round robin creates every possible parlay combination from a set of teams. Enter your teams, choose your parlay size, and set your per-parlay wager.
A round robin takes a group of teams and automatically builds every possible parlay combination. A 3-team round robin of 2-team parlays creates 3 separate parlays: A+B, A+C, and B+C.
The advantage: You do not need all teams to win. If 2 of 3 teams win, some parlays still cash — protecting against a single loss wiping everything out.
The tradeoff: You wager on each combination separately, so total stake is higher. Use round robins when you have moderate confidence in several teams but want protection against one miss.