betROI.xyz is a free collection of sports betting calculators for bettors who take their results seriously. Every tool runs entirely in your browser — no data is collected, no signup required.
Calculate your return on investment from betting history. Track profit, loss, and win rate.
Manage your betting budget. Supports flat, percentage, and Kelly staking methods.
Find the mathematically optimal stake size given your edge and the offered odds.
Calculate combined odds, payout, and true win probability for multi-leg bets.
Find guaranteed profit stakes across two or three bookmakers.
Convert between decimal, American, and fractional odds instantly.
Most bettors don't track their results properly. They remember the wins and forget the losses. Our ROI calculator makes it simple to get an honest picture of your betting performance over time.
The tools are built on established mathematical frameworks — Kelly Criterion, arbitrage theory, probability — not hunches. We believe better information leads to better decisions.
All calculations happen in your browser using JavaScript. We never see your numbers. See our privacy policy for details.