The probability of an outcome as implied by the betting odds, including the bookmaker's margin.
Implied probability converts betting odds into a percentage chance of an outcome occurring. It reflects what the market believes the probability is, but it includes the bookmaker's margin (vig), so implied probabilities for all outcomes always sum to more than 100%.
Comparing implied probability to your own estimated probability is the foundation of value betting. If you believe a team has a 60% chance of winning but the odds imply only 50%, that's a +EV bet.
You can calculate implied probability from any odds format: American, decimal, or fractional.
You see the Lakers at -180 on FanDuel. American odds of -180 mean you risk $180 to win $100, which translates to an implied probability of 180 / (180 + 100) = 64.3%. This is the break-even point: if the Lakers win more than 64.3% of the time at this price, the bet is profitable long-term.
Compare against a +250 underdog: implied probability is 100 / (250 + 100) = 28.6%. Combined, the two sides add to 92.9%, leaving 7.1% as the sportsbook's hold. Sharp bettors strip out the hold using a no-vig calculation before deciding which side carries actual edge — a +250 underdog with a fair-odds estimate of 35% is +EV, even though it loses 65% of the time.
For negative American odds: IP = |odds| / (|odds| + 100). For positive: IP = 100 / (odds + 100)<p>You see the Lakers at <strong>-180</strong> on FanDuel. American odds of -180 mean you risk $180 to win $100, which translates to an implied probability of <strong>180 / (180 + 100) = 64.3%</strong>. This is the break-even point: if the Lakers win more than 64.3% of the time at this price, the bet is profitable long-term.</p><p>Compare against a +250 underdog: implied probability is <strong>100 / (250 + 100) = 28.6%</strong>. Combined, the two sides add to 92.9%, leaving 7.1% as the sportsbook's hold. Sharp bettors strip out the hold using a no-vig calculation before deciding which side carries actual edge — a +250 underdog with a fair-odds estimate of 35% is +EV, even though it loses 65% of the time.</p>
The commission a sportsbook charges on a bet, built into the odds.
The actual mathematical probability of an outcome, without any bookmaker margin.
The average amount you can expect to win or lose per bet over time.
The true fair odds after removing the sportsbook's built-in margin.
The probability of an outcome as implied by the betting odds, including the bookmaker's margin.
For negative American odds: IP = |odds| / (|odds| + 100). For positive: IP = 100 / (odds + 100)
<p>You see the Lakers at <strong>-180</strong> on FanDuel. American odds of -180 mean you risk $180 to win $100, which translates to an implied probability of <strong>180 / (180 + 100) = 64.3%</strong>. This is the break-even point: if the Lakers win more than 64.3% of the time at this price, the bet is profitable long-term.</p><p>Compare against a +250 underdog: implied probability is <strong>100 / (250 + 100) = 28.6%</strong>. Combined, the two sides add to 92.9%, leaving 7.1% as the sportsbook's hold. Sharp bettors strip out the hold using a no-vig calculation before deciding which side carries actual edge — a +250 underdog with a fair-odds estimate of 35% is +EV, even though it loses 65% of the time.</p>
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