Rex says
The fast lane for the math you almost remember from school. Type the numbers, get the answer, move on with your day.
Try a scenario
Click to load — tweak from there.Inputs
Result
Break-even win rate
52.38%
Wins needed per sample
52.4
Losses allowed per sample
47.6
ROI if you actually win 55%
5.0%
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How to use this
- 1Enter american odds.
- 2Enter bets to project.
- 3Read your break-even win rate on the right — it updates as you type.
- 4Hit Share to keep the scenario or send it to someone.
About this calculator
At standard -110 odds, most bettors assume they need to win 50% of bets to break even, but the vig means the real number is 52.38%. That 2.38-point gap is the entire reason casual sports betting is a losing proposition over time for the average bettor: you're not just betting against the other side, you're betting against the house's built-in cut on every wager. This calculator generalizes the math beyond -110 to any American odds, so you can see exactly what win rate a specific line requires before it turns a profit. It also shows how many units you'd need to win out of 100 bets at that price, translating an abstract percentage into a concrete record you can compare against your actual betting history. If you track your bets (and you should), this number is the benchmark: a win rate below the break-even threshold at your average odds means you're losing money regardless of how the highlight-reel wins felt.
Worked example
Using the values the calculator loads with:
Inputs
- American odds: -110
- Bets to project: 100
Results
- Break-even win rate: 52.38%
- Wins needed per sample: 52.4
- Losses allowed per sample: 47.6
- ROI if you actually win 55%: 5.0%
What each field means
Inputs
- American odds
- The american odds used in the calculation. Starts at -110 so you have a working example on load.
- Bets to project
- The bets to project used in the calculation. Starts at 100 so you have a working example on load.
Results
- Break-even win rate
- Returned as a percentage and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Wins needed per sample
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Losses allowed per sample
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- ROI if you actually win 55%
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why is break-even 52.38% instead of 50% at -110?
Because -110 means risking $110 to win $100, not an even $100-for-$100 bet. The extra $10 you have to risk relative to your potential win is the vig, and it shifts the true break-even point above a coin flip. Winning exactly half your -110 bets loses money steadily over time.
What win rate do professional sports bettors actually achieve?
Widely-cited estimates for long-term winning bettors (against the spread, at standard vig) sit in the 53-55% range, and even the best documented handicappers rarely sustain much above 55-57% over large samples. This context matters: a 60%+ long-run win rate at standard odds is exceptionally rare, not typical of a 'good' bettor.
Does the break-even rate change with plus-money odds?
Yes, and it drops as the underdog price gets bigger. At +150 you only need to win about 40% of the time to break even, because each win pays more than the stake. At +300, break-even drops to 25%. Longer odds require a lower win rate but higher variance in your results.
How many bets do I need before my win rate is meaningful?
Standard deviation on binary outcomes means small samples are noisy — 20 or 50 bets can easily show a win rate several points off your true long-run rate purely by chance. Most serious bettors want at least several hundred bets, ideally over 1,000, before trusting a win-rate number as representative.
Accuracy and limitations
- Results are rounded for display; the underlying calculation keeps full precision.
- Very large or very small inputs may hit floating-point limits in the browser.
- Inputs outside the accepted range are clamped rather than rejected.
Related tools
Expected Value (EV) Bet Calculator
Find the dollar EV of a wager given your true win probability.
Closing Line Value (CLV) Calculator
Measure whether you beat the market's final price, independent of the result.
Bankroll Risk of Ruin Calculator
Estimate the odds of busting your bankroll at a given edge and bet size.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Break-Even Win Rate Calculator (-110 and Beyond). Retrieved from https://www.revenuelab.fyi/toolbox/breakeven-win-rate-calculator
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/breakeven-win-rate-calculator" target="_blank" rel="noopener">Break-Even Win Rate Calculator (-110 and Beyond) — RevenueLab</a> (2026).</p>
Source: [Break-Even Win Rate Calculator (-110 and Beyond) — RevenueLab](https://www.revenuelab.fyi/toolbox/breakeven-win-rate-calculator) (2026).