Most novice bettors look at the odds first and decide if they like the team. Professional bettors do the opposite: they calculate the probability of the team winning first, and then check if the odds offer any value.
Our True Odds Calculator is the ultimate handicapping tool. By inputting your estimated win probability (e.g., “I give them a 60% chance”), it instantly generates the “Fair Odds”—the mathematical break-even price. Compare this against the bookmaker’s line to instantly spot +EV (Expected Value) opportunities.
True Odds Generator
Prob % → OddsHow to Use the True Odds Generator
This tool is designed to reverse-engineer the betting line based on your handicapping. Here is the workflow:
- Enter Your Probability: Input the percentage chance you believe the outcome has of winning (0.1% to 99.9%).
- Example: If you think a tennis player wins this match 3 out of 4 times, enter 75%.
- Enter Bookmaker Odds (Optional): If you are looking at a specific sportsbook line, enter their odds here (Decimal format is standard, e.g., 2.50).
- Analyze the Results:
- True Odds: This is the price at which the bet breaks even. If you accept odds lower than this, you will lose money in the long run.
- Value Check: If you entered Bookmaker Odds, the calculator will show your ROI (Return on Investment). Green means the bet is profitable (+EV); Red means it is a bad bet (-EV).
Related Tools: If you want to do the opposite—take the bookie’s odds and see what probability they imply—use our Implied Probability Calculator. Once you find a value bet, use the Kelly Criterion Calculator to determine exactly how much to wager.
Real-World Examples: Finding Value
The concept of “True Odds” is the cornerstone of profitable sports betting. Here is how it works in practice.
Example 1: The Undervalued Underdog
You analyze a UFC fight and believe the underdog has a 40% chance of winning.
- True Odds Calculation: 100 / 40 = 2.50 (+150).
- The Offer: The bookmaker is offering odds of 2.80 (+180).
- Verdict: Because the bookie is paying 2.80 for an event that should be priced at 2.50, this is a Value Bet with massive +EV. You should bet this every time.
Example 2: The Overvalued Favorite (The Trap)
Manchester City is playing, and you think they have an 80% chance to win.
- True Odds Calculation: 100 / 80 = 1.25 (-400).
- The Offer: The bookmaker is offering odds of 1.15 (-660).
- Verdict: Even though 80% is a high probability, the odds of 1.15 are “too short.” The risk outweighs the reward. This is Negative EV, and you should skip the bet.
Frequently Asked Questions (FAQ)
What are “True Odds”?
True Odds (or Fair Odds) represent the exact mathematical probability of an event occurring without any bookmaker margin (vig) added. If you bet on True Odds forever, you would exactly break even (0% profit/loss).
How do I estimate the winning probability?
This is the “art” of handicapping. You can use historical data, Elo ratings, power rankings, or your own knowledge of injuries and weather conditions. The goal of a bettor is to create a probability model that is more accurate than the bookmaker’s model.
Why are bookmaker odds always lower than True Odds?
Bookmakers build a margin (called “Vig” or “Juice”) into their lines to ensure profit. For example, on a coin flip (50% probability), True Odds are 2.00. A bookmaker will offer 1.90. The difference is their fee.
What is +EV (Expected Value)?
+EV means that if you placed the same bet an infinite number of times, you would end up with a profit. It occurs whenever the Bookmaker’s Odds are higher than the True Odds derived from the actual probability.