Free Expected Value (EV) Calculator for Sports Betting

Use this expected value calculator to quickly determine whether a bet is mathematically profitable. By entering the bookmaker’s odds, your estimated win probability, and your stake amount, you can instantly calculate the expected value of a wager and see whether it qualifies as a positive EV (+EV) or negative EV (-EV) opportunity.

Simply input your probability percentage, the odds offered, and how much you plan to bet. The calculator will show your implied probability, probability edge, break-even percentage, expected value, and projected ROI within seconds.

If you want a deeper explanation of how professional bettors use +EV strategies long term, read our full +EV betting guide.

Expected Value (EV) Betting Calculator

Use the calculator above to determine whether your bet has positive or negative expected value based on your own probability estimate.

Inputs

• Win Probability (%) – Your estimated chance of the bet winning.
• Odds (Decimal default) – The bookmaker’s offered odds for the selection.
• Stake Amount – The amount you plan to wager.

Outputs

• Expected Value (Money) – The projected profit or loss per bet based on your inputs.
• EV Percentage – Your expected return relative to your stake.
• Positive / Negative Label – Clear indication of whether the bet is +EV or -EV.
• One-line interpretation –
  • “This bet has positive expected value.”
  • “This bet has negative expected value.”

Enter your numbers and click calculate to see the result instantly.

How to Calculate Expected Value in Betting

Follow these simple steps to calculate the expected value of your bet:

1. Enter your estimated win probability as a percentage based on your own analysis.
2. Enter the bookmaker odds for the selection you’re considering.
3. Enter your stake amount, the amount you plan to wager.
4. Click “Calculate.”
5. Review the result to see whether the bet shows positive or negative expected value.

If the result is positive, the bet has a mathematical edge. If it is negative, the bet is expected to lose money over time.

Expected Value Formula in Sports Betting

The expected value of a bet is calculated using the following formula:

EV = (Probability × Profit Per Win) − (Loss Probability × Stake)

This formula measures the average amount you can expect to win or lose per bet based on your estimated probability and the odds offered.

• Probability – Your estimated chance of the bet winning, expressed as a decimal (for example, 55% becomes 0.55).
• Profit Per Win – The net profit you would receive if the bet wins, calculated from the odds and your stake (not including your original stake).
• Loss Probability – The chance of the bet losing, calculated as 1 minus your win probability.

If the final EV number is positive, the bet has positive expected value. If it is negative, the bet is expected to lose money over time.

Expected value is a standard concept in probability theory used to measure the average outcome of repeated events. You can read more about the mathematical definition of expected value on educational resources such as Wikipedia.

Example of an EV Calculation

Let’s use a simple example to see how expected value works in practice.

• Win Probability: 55% (0.55)
• Odds: 2.00 (Decimal)
• Stake: $100

First, calculate the potential profit if the bet wins:

Profit per win = (2.00 − 1) × $100 = $100

Loss probability = 1 − 0.55 = 0.45

Now apply the EV formula:

EV = (0.55 × 100) − (0.45 × 100)
EV = 55 − 45
EV = $10

This means the bet has a positive expected value of $10 per $100 wagered, based on your probability estimate.

What Does Positive or Negative EV Mean?

A positive expected value (EV) means that, based on your probability estimate, the bet is profitable over many similar wagers. If you were to place the same type of +EV bet repeatedly under the same conditions, the average outcome would be positive over time.

A negative expected value (EV) means the bet is expected to lose money over many similar attempts. Even if it wins occasionally, the long-term average result would trend negative.

It’s important to understand that EV does not guarantee short-term results. A positive EV bet can still lose on any single attempt. Expected value reflects long-term expectation, not immediate outcomes.

More Betting Calculators

If you’re analysing your bets seriously, you may also find these tools useful:

• Value Betting Calculator – Compare true probability against implied odds to identify mispriced lines.
• Hedge Betting Calculator – Calculate how much to hedge to lock in profit or reduce risk.
• Betting Units Calculator – Determine optimal bet sizing based on your bankroll.
• Parlay Calculator – Calculate total payout and odds for multi-leg accumulator bets.

Using these calculators together helps you evaluate edge, manage risk, and structure your betting decisions more effectively.

Frequently Asked Questions

How do I estimate probability for EV?

To estimate win probability, use your own analysis such as team form, player statistics, historical data, or model projections. Enter your best percentage estimate into the calculator to compare it against the bookmaker’s implied probability.

What is a good EV percentage?

A good EV percentage is any positive value. The higher the positive EV, the stronger the mathematical edge based on your probability estimate. Even small positive percentages can add up over many similar bets.

Why is my EV negative?

Your EV is negative when your estimated probability is lower than the break-even probability implied by the odds. This means the bet is expected to lose money on average based on your inputs.

Can I use this EV calculator for parlays?

Yes, but you must first convert your parlay into combined decimal odds and estimate the overall win probability. Then enter those values into the calculator to determine the expected value.

Does EV guarantee profit?

No. Expected value reflects long-term expectation, not short-term results. A positive EV bet can still lose on a single attempt, but over many similar bets, the average result should trend positive based on your estimates.