Implied Probability Calculator
Convert between betting odds and win probability
Calculate Implied Probability
Conversion direction:
Get today's top +EV picks — free
Done crunching the numbers? Our model scans FanDuel & DraftKings for positive-EV bets. Get the day's best delivered free — no spam, unsubscribe anytime.
The FairLine™ runs this math across every game, every market
You ran the numbers on one bet. We run them continuously across FanDuel and DraftKings, with the FairLine math exposed on every flag and every result graded in a public W-L ledger you can audit before subscribing.
7-day free trial • Cancel anytime
What is Implied Probability?
Implied probability is the conversion of betting odds into a percentage that represents the likelihood of an outcome occurring according to the sportsbook's odds.
The Formula: Implied Probability = (1 / Decimal Odds) × 100
For example, odds of 2.00 (decimal) or +100 (American) imply a 50% probability. This means the sportsbook's odds suggest the event has a 50% chance of happening.
Why Implied Probability Matters
Understanding implied probability is crucial for identifying value bets:
Compare your analysis - If you think a team has a 60% chance to win but the odds imply only 50%, you may have found value
Understand the vig - When implied probabilities for all outcomes exceed 100%, the difference is the sportsbook's margin
Make informed decisions - Knowing the breakeven win rate helps you decide if a bet is worth taking
Implied Probability Quick Reference
| American Odds | Decimal Odds | Implied Probability | Interpretation |
|---|---|---|---|
| -1000 | 1.10 | 90.91% | Heavy favorite |
| -500 | 1.20 | 83.33% | Strong favorite |
| -200 | 1.50 | 66.67% | Moderate favorite |
| -110 | 1.91 | 52.38% | Slight favorite (standard line) |
| +100 | 2.00 | 50.00% | Even money / coin flip |
| +110 | 2.10 | 47.62% | Slight underdog |
| +200 | 3.00 | 33.33% | Moderate underdog |
| +500 | 6.00 | 16.67% | Strong underdog |
| +1000 | 11.00 | 9.09% | Heavy underdog / long shot |
Implied Probability FAQs
How do I calculate implied probability manually?
For decimal odds: Implied Probability = (1 / Decimal Odds) × 100. For American odds (+): Implied Probability = 100 / (American + 100) × 100. For American odds (-): Implied Probability = |American| / (|American| + 100) × 100. Example: -110 odds → 110 / (110 + 100) = 110 / 210 = 52.38%.
Why is implied probability important for betting?
Implied probability shows you the breakeven win rate for a bet. If you consistently bet at odds that imply 50% but win 55% of the time, you will be profitable long-term. The gap between implied probability and your true probability estimate is your edge.
What if I think the true probability is lower than implied?
If you believe the true probability is lower than the implied probability, you should consider betting the other side (if available) or avoiding the bet entirely. For example, if odds imply a 60% win probability but you think it is only 50%, the bet has negative expected value.
How does the vig affect implied probability?
The vig (or juice) is built into the odds by the sportsbook. This is why the implied probabilities of all outcomes in a market sum to more than 100%. For example, -110 on both sides of a spread has a combined implied probability of 104.76%, with the extra 4.76% representing the sportsbook’s margin.
What are no-vig or fair odds?
No-vig (or fair) odds are the true odds after removing the sportsbook’s margin. These represent the actual implied probability of each outcome. You can calculate no-vig odds using our Vig Calculator. Finding bets at odds better than the no-vig odds is key to profitable betting.
Using Implied Probability in Your Betting
Finding Value Bets
The key to profitable betting is finding situations where your estimated probability exceeds the implied probability. Here's a simple framework — or skip the manual work and see how we automate it as an OddsJam alternative:
1. Estimate - Research the matchup and estimate the true probability
2. Compare - Convert the odds to implied probability using this calculator
3. Evaluate - If your estimate is significantly higher, you may have found value
4. Size - Use the Kelly Criterion to determine optimal bet size based on your edge
Example Analysis
Scenario: Lakers at +150 vs Celtics
Implied probability: 40%
Your analysis: You believe the Lakers have a 50% chance to win based on injuries, rest, and recent form.
Edge: 50% - 40% = 10% edge
Expected Value: (0.50 × $150) - (0.50 × $100) = $75 - $50 = +$25 per $100 bet
This represents a strong +EV opportunity if your probability estimate is accurate.
Related Resources
Embed this calculator on your site
Free for any site, blog, or forum thread. Pick a size, copy the code, paste anywhere. Embeds include a small "Powered by +EV Bets" link in the footer. No attribution required, no analytics, no data shared with us.