Expected Value Betting Calculator – see, in real time, whether a wager is +EV or –EV
What is expected value in betting?
Expected value (often shortened to EV) is the long‑run average amount you can expect to win —or lose —per bet if you placed the same wager thousands of times.
- Positive EV (+EV) means the bet is mathematically profitable.
- Negative EV (–EV) means the odds are stacked against you.
Understanding EV lets you separate genuine value bets from expensive hunches.
How the calculator works
| Input | Description | Example |
|---|---|---|
| Wager | Your stake size in any currency. | 100 $ |
| Odds | Decimal odds (use our Odds Converter if needed). | 2.20 |
| Win Probability | Your predicted chance of success (in %). | 60 % |
The tool instantly returns Expected Value in your chosen currency and flags it profitable (green) if EV > 0 or unprofitable (red) if EV < 0.
Example:
Stake = 100 $, Odds = 2.20, Win Prob = 60 %
EV = (0.60 × (2.20 × 100 – 100)) – (0.40 × 100) = 32 $ → +EV
Why EV matters for every bettor
- Quantifies edge – Know exactly how much you stand to gain (or lose) on average.
- Eliminates guesswork – Replace “I feel good about this pick” with cold, hard maths.
- Optimises bankroll strategy – Use EV together with the Kelly Criterion Calculator to size stakes efficiently.
- Highlights bookmaker bias – Spot overpriced or under‑priced markets at a glance.
Step‑by‑step: using the EV calculator
- Enter your stake – type any whole or decimal number.
- Input the market odds – decimal format (or convert).
- Estimate true probability – from models, stats, or expert judgement.
- Read the result – positive = bet has value; negative = pass or reduce stake.
- Compare multiple markets – rinse and repeat to build a +EV portfolio.
Pro tip: Track every wager in a spreadsheet; over time your actual ROI should converge toward the average EV of the bets you place.
The maths behind expected value
For a single‑outcome wager:
Net profit if bet wins = (odds × stake) – stake
Net loss if bet loses = stake
EV = (win_prob × net_profit) – ((1 – win_prob) × stake)
Because EV is an average across infinitely many trials, even +EV bets will lose sometimes. Bankroll management is therefore essential.
Frequently asked questions
Is +EV a guarantee I’ll win?
No. It means you should win in the long run, but variance can hurt in the short term.
How do I estimate true probability?
Use historical data, statistical models, expert ratings or market‑based signals. The more accurate your estimate, the more reliable the EV output.
Can I use implied probability instead of my own?
You can, but then EV always lands negative because the bookmaker’s margin is baked in. To uncover value you need a better probability than the book offers.
Does EV work for parlays and multiples?
Yes—multiply the leg probabilities and combined odds, then feed them into the calculator.