Expected Value (EV) Calculator
Determine if a bet has positive expected value for long-term profitability
Bet Parameters
Odds offered by bookmaker
Your assessed probability based on analysis
Expected Value
Enter bet details and click calculate
Professional Insight
Professional bettors only place bets with positive expected value (+EV). The higher the EV percentage, the better the bet. Consistent +EV betting guarantees long-term profit despite short-term variance.
Understanding Expected Value
Expected Value (EV) is the average amount you can expect to win or lose per bet over the long term. It's the most fundamental concept in professional sports betting.
EV = (Probability of Win × Profit) - (Probability of Loss × Stake)
Positive EV (+EV)
When your assessed probability is higher than the bookmaker's implied probability, the bet has positive expected value. These are the only bets professionals take.
Negative EV (-EV)
When the bookmaker's implied probability is higher than your assessment, the bet has negative expected value. Avoid these bets completely.
Example: You assess Springboks have 55% chance to win. Hollywood Bets offers 2.00 odds (50% implied). This is a +EV bet because your probability (55%) exceeds implied probability (50%).
Find +EV Opportunities
Apply expected value analysis on platforms with competitive odds and deep markets
How to use this expected value calculator
Work through a rand example
Supply decimal odds, your estimated winning probability and the amount at risk. As an illustration, suppose the price is 2.20, your estimate is 50% and the stake is R100. EV per R1 = p × (odds - 1) - (1 - p). Substituting these assumptions gives 0.50 × 1.20 - 0.50 = R0.10 per rand. Multiplying by R100 produces an expected value of R10.
Separate expectation from settlement
That R10 is a probability-weighted average, not the payout on a single ticket. This example either earns R120 net profit when successful or loses R100. A positive reading depends entirely on the quality of the probability supplied. It cannot establish that your estimate is correct.
Check sensitive inputs
Try a lower winning estimate before deciding whether a marginal edge is convincing. Avoid confusing the total return with profit, typing fractional odds into a decimal field, or treating bookmaker implied probability as an independent prediction. Keep a note of your reasoning before kickoff so the eventual result does not rewrite it.
Can positive EV bets still lose?
Yes. Favourable expectation leaves uncertainty in every outcome. Restrict stakes to an affordable entertainment allowance and stop when your preset spending boundary is reached.
Does changing the stake improve value?
A bigger stake scales both the expected amount and potential loss. It does not improve the underlying percentage edge or make an uncertain selection safer.