Positive EV Betting Formula Explained

Expected value tells you whether a price is profitable over the long run, not whether one ticket wins tonight.

The Core +EV Formula#

Use this formula:

• EV = (Win Probability x Profit if Win) - (Lose Probability x Stake)

Where:

• Win Probability is your own projected percentage converted to decimal.
• Lose Probability = 1 - Win Probability.
• Profit if Win depends on the market odds and your stake.

Break-Even Probability#

Every market price has a minimum required win rate.

• Break-Even % = (1 / Decimal Odds) x 100

If your projection is above break-even, your edge is positive.

Quick Example#

• Stake: $100
• Market odds: 2.10 decimal
• Your projected win probability: 52%

Math:

• Profit if win = $110
• EV = (0.52 x 110) - (0.48 x 100) = 57.2 - 48 = +$9.20
• EV% = 9.20%

This is a positive expected value setup.

Practical Workflow#

1. Convert the market odds to implied and break-even percentage.
2. Build your own win probability estimate.
3. Compute EV and edge.
4. Only consider bets with meaningful positive EV.

Use the +EV Calculator for the full EV output, the Odds Converter for fast format conversion, and the How to Use the +EV Calculator guide for a step-by-step workflow.