Expected Value (EV) Calculator
Compute the expected value, ROI, and break-even probability of any bet in one click. The single most important number in sports betting — if you can't compute EV, you're guessing.
What is Expected Value?
Expected value (EV) is the average amount you win or lose per unit staked, repeated over an infinite number of identical bets. If a coin flip pays you €2.10 for every €1 staked, EV = (0.5 × 1.10) − (0.5 × 1.00) = +€0.05 per €1, or +5% per bet. After 10,000 flips, you'd expect +€500.
The formula
Where:
- p = your true probability of winning (e.g. 0.55)
- odds = decimal odds offered (e.g. 2.10)
Multiply by your stake to get EV in money. EV ≥ 0 = profitable long-term. EV < 0 = guaranteed losses if repeated.
Break-even probability
The break-even probability is the minimum win rate that makes a bet profitable at given odds. It's just the implied probability of those odds:
If you can't honestly say your win probability is higher than the break-even, the bet has negative EV. Don't take it.
What's a "good" EV?
| EV per bet | Quality | Real-world |
|---|---|---|
| 0% to +1% | Marginal | Below most operators' vig — usually noise |
| +1% to +3% | Solid | Sharp territory — profitable with enough volume |
| +3% to +6% | Strong | Most pro models target this band |
| +6% to +10% | Very strong | Either you found a stale line or an outlier |
| +10% to +20% | Suspicious | Usually means your probability is wrong, OR the line moved |
| +20%+ | Almost always wrong | Either arbitrage or you're miscounting — re-check |
TIPERO's typical bet has +5% to +12% EV at the time of selection, declining to +2% to +6% by closing line as the market converges. Maintaining +EV against the closing line (CLV) is the real test of model skill — see our CLV guide.
EV vs. Hit Rate — why the latter doesn't matter
A 70% hit rate at odds of 1.30 has EV = 0.7 × 0.30 − 0.3 × 1.00 = −9% per unit. Losing money.
A 35% hit rate at odds of 3.20 has EV = 0.35 × 2.20 − 0.65 × 1.00 = +12% per unit. Crushing it.
This is why TIPERO publishes ROI in units, not just hit rate. Tipsters who only show "70% accuracy" usually pick favourites that lose money long-term.
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What is expected value in betting?
The average amount a bet wins or loses per unit staked over an infinite number of identical placements. Positive EV = profitable long-term, negative = loses money.
How is EV calculated?
EV per unit = p × (odds − 1) − (1 − p), where p is your true probability and odds is decimal. Multiply by stake for money.
What's a realistic EV target?
+2% to +8% per bet, sustained, is sharp territory. +10%+ is suspicious — either you found a stale line or your probability estimate is too aggressive.
Why does EV matter more than hit rate?
You can have a 70% hit rate and still lose money if you're betting heavy favourites at terrible odds. EV combines win rate AND price into one honest number.
Can EV be negative even when I win?
Yes. Single-bet outcomes are random; EV describes the long-run average. A −EV bet can win, but if you repeat it 1000 times you'll lose money on net.