The simplest, fastest betting math: enter your stake and the American odds, and we'll show your profit if the bet wins, total return, ROI percentage, and the implied probability baked into the price. Last updated: May 2026.
Everything here flows from one conversion: American odds to decimal. Positive odds become (odds ÷ 100) + 1; negative odds become (100 ÷ |odds|) + 1. Once the price is in decimal form, the rest is straightforward arithmetic. Profit = stake × (decimal − 1), because the "− 1" strips out your returned stake and leaves only winnings. Total return = stake × decimal, the full amount the book hands back when you win.
The calculator also reports ROI and implied probability. ROI = profit ÷ stake × 100, which is identical for any stake at the same odds — a property that makes ROI the cleanest way to compare prices. Implied probability = 1 ÷ decimal × 100, the break-even win rate the line is charging you. "Loss if lose" is simply your stake back as a negative number, a reminder that the downside is always 100% of what you put up.
Default inputs: a $100 stake at −110. Convert the odds: (100 ÷ 110) + 1 = 1.909 decimal. Profit = $100 × (1.909 − 1) = $100 × 0.909 = $90.91. Total return = $100 × 1.909 = $190.91 — your $100 back plus $90.91 in winnings.
ROI = $90.91 ÷ $100 = 90.91%, and that figure holds whether you bet $10 or $10,000 at −110. Implied probability = 1 ÷ 1.909 = 52.38%, the win rate you'd need just to break even at this price. If you instead entered +150, decimal becomes 2.50, profit jumps to $150, total return to $250, ROI to 150%, and implied probability falls to 40% — bigger payout, longer odds. The "Loss if lose" line stays at −$100 either way.
This calculator shows the gross payout the book has priced — it doesn't judge whether the bet is smart. A fat profit figure at long odds still loses most of the time, so weigh the implied probability against your honest read before risking money you can't afford to lose.
For positive odds (+150): profit = stake × (odds ÷ 100). For negative odds (-110): profit = stake × (100 ÷ |odds|). Total return is profit plus your original stake.
Profit is what you win on top of your stake. Total return is profit plus stake — the amount the book actually pays out to you. A $100 bet at +200 has $200 profit and $300 total return.
Return on investment — your profit expressed as a percentage of your stake. A $100 bet that wins $200 has 200% ROI. ROI is identical for the same odds regardless of stake size.
The win rate baked into the offered odds. It's 1 ÷ decimal odds. If your true win probability beats it, the bet is +EV. If not, the bet is -EV.
This calculator shows the payout exactly as the book has priced it — the vig is already inside the odds. To see the no-vig fair price, use the odds converter and back out the juice manually.