Expected Value (EV) Calculator

Short winning streaks at -EV odds are noise. Consistent +EV with disciplined probability sourcing is signal. EV forces you to separate two questions: Is this a good price? and Do I think this side wins? Without a probability estimate you can defend, you cannot answer the first question at all.

Closing Line Value (CLV) is the leading indicator that your probability estimates are calibrated. If your bets consistently open at better prices than where they close, your process is capturing real information about the market. CLV tracks whether your price advantage is repeatable - not just lucky.

Treat EV as bookkeeping on whether a price clears your threshold. A single positive EV result means nothing. A hundred of them means your inputs were honest.

EV = (Win probability x Profit if win) - (Loss probability x Stake). Multiply your estimated win chance by the profit you collect if correct, then subtract the stake times the chance you lose. That is the full calculation.

The common mistake is using the book's own implied probability as the Win % input. That always returns zero EV before vig and negative after it. Your estimate needs to come from somewhere independent - a sharp market stripped of vig, a power rating, or your own model.

Pinnacle and Circa price two-sided action from sophisticated bettors and adjust accordingly. Strip the vig off their lines using the no-vig calculator and you have the sharpest publicly available reference for fair win probability.

The Win % field is the most important input. Enter the probability you actually believe, not the book's implied number. If you do not have a defensible estimate, the EV output is meaningless regardless of what it prints.

Read EV % and Profit If Win together. High Profit If Win with negative EV % means the payout is enticing but your probability says to pass.

You find a prop at +150 and your model says the true win probability is 45%. Stake $100. Profit if win = $150. Loss probability = 55%.

EV = (0.45 x $150) - (0.55 x $100) = $67.50 - $55.00 = +$12.50. EV % = 12.5%. That is a meaningful edge.

For comparison, if you used the book's implied probability of 40% (which is what +150 implies before vig) as your Win %: EV = (0.40 x $150) - (0.60 x $100) = $60 - $60 = $0 before vig, and negative after it. The entire edge lives in whether you trust your estimate over the book's price.

The biggest mistake is plugging the book's implied probability into Win %. That makes EV zero or negative by definition. Your estimate needs an independent source.

Single-game samples fool bettors into thinking a hot streak confirms their model. Track EV across at least 100 bets before drawing calibration conclusions.

Ignoring line movement is another leak. If a line opens at +150 and closes at -110, the market is pricing the true probability near 52%, not the 40% your original price implied. Use CLV as feedback to improve estimates over time.