Odds Conversion Calculator | Universal Betting Tool
Convert between American, Decimal, and Fractional betting odds instantly while calculating implied probability and potential payouts.
Enter Your Odds
Choose the format your sportsbook or source uses
Enter odds in your selected format
Optional: Enter wager to see payout
Implied Probability
Win likelihood based on odds
Converted Odds Formats
Click value to copyUnderstanding implied probability
Implied probability is the single most important concept separating casual bettors from sharp bettors. It represents the sportsbook's assessment of the likelihood of an outcome, baked directly into the odds.
When you see odds of −110 (American) or 1.91 (Decimal), the sportsbook is implying a specific percentage chance that the event will happen. If your personal estimate of the true probability is higher than the implied probability, you have identified a value bet.
The three odds formats explained
| Format | Region | How it works |
|---|---|---|
| American | USA | Positive (+): profit on a $100 bet (e.g. +200 = win $200). Negative (−): amount to bet to win $100 (e.g. −150 = bet $150 to win $100). |
| Decimal | Europe, Canada, Australia | Multiply your stake by this number to get the total payout (stake + profit). |
| Fractional | UK, Ireland | Represents profit per unit stake. 5/2 means $5 profit for every $2 wagered. |
Why convert odds?
- Compare lines. Sportsbooks often display different formats. Converting them to a common language (like decimal) allows for instant price comparison.
- Find value. It is easier to compare your own probability estimate (e.g. "I think they have a 60% chance") against implied probability in percent than against −150 odds.
- Bankroll management. Proper staking methods like the Kelly criterion require decimal odds or probability inputs.
Payout vs. profit: know the difference
One of the most common mistakes for new bettors is confusing "payout" with "profit".
- Payout (return): the total money the sportsbook sends to your account if you win. This includes your original stake being returned.
- Profit (net win): the actual money you made. Calculation:
payout − original stake.
Example: $100 bet at 2.00 (decimal) odds. Payout = $200. Profit = $100.
Finding value: true odds vs. implied odds
Profitable betting isn't about picking winners; it's about picking prices that are wrong. This is the concept of value.
- Your estimate. You analyse a game and determine Team A has a 55% chance of winning. This is your "true probability".
- The sportsbook. The book offers +100 (2.00) odds. This implies a 50% probability.
Since your true probability (55%) is greater than the implied probability (50%), this is a value bet.
Frequently asked questions
Why don't the odds on both sides sum to 100%?
The difference is the sportsbook's "vig" or "juice" — their built-in profit margin. For example, −110 on both sides implies ~52.38% on each, totalling ~104.76%. The extra ~4.76% is the book's edge.
Can I use this calculator for live/in-play betting?
Absolutely. Odds change constantly during live events. The calculator instantly converts any odds entered, allowing you to make informed decisions in real time.
How do I find arbitrage opportunities?
Compare odds on the same event across multiple sportsbooks. Convert all to decimal format. If the sum of (1 / odds) for all possible outcomes is less than 1, an arbitrage opportunity exists.
Is there a best odds format?
Mathematically, decimal is the simplest and most versatile for calculations. However, use whatever format you are most comfortable reading quickly.