Every moneyline carries a hidden number most bettors ignore: the implied probability. That number tells you what the sportsbook thinks the win percentage is. Learn to read it, and you can spot when a line offers value — and when it doesn't.
What exactly is implied probability?
Implied probability is the win percentage baked into a set of odds. A –200 favorite carries an implied probability of roughly 66.7%. That means the sportsbook is pricing that team as a two-in-three shot to win. Before placing any wager, knowing that number is essential. Check out How to Read Moneyline Odds: Positive, Negative, and Pick 'Em if the +/– format still feels unfamiliar.
How do you convert a moneyline to a win percentage?
Two formulas cover every situation:
- Favorite (negative odds): |odds| ÷ (|odds| + 100) × 100. At –200: 200 ÷ 300 × 100 = 66.7%.
- Underdog (positive odds): 100 ÷ (odds + 100) × 100. At +200: 100 ÷ 300 × 100 = 33.3%.
Notice those two numbers add up to 100%? In a fair market they would. They don't because of the vig.
Why does the vig matter so much?
The vig is the sportsbook's built-in commission. On a standard pick 'em priced –110 / –110, each side carries an implied probability of about 52.4%. Add them up and you get roughly 104.8%, not 100%. That extra 4.8% is the house edge. To break even on –110 bets long-term, a bettor must win 52.4% of the time — not just 50%. For a deeper look at how the vig shapes every line, see Moneyline Betting Strategy: How to Spot Value and Avoid the Vig.
What does implied probability look like across common lines?
| Moneyline | Implied Probability | Side |
|---|---|---|
| –200 | ~66.7% | Favorite |
| –110 | ~52.4% | Pick 'em favorite |
| +150 | ~40.0% | Underdog |
| +300 | ~25.0% | Heavy underdog |
How do you use this to find value?
Value exists when your own estimated win probability is higher than the implied probability the line suggests. If a team is priced at –130 (implied ~56.5%) and you believe they win 65% of the time, that's a value spot. No guarantee of winning — but positive expected value over time. Moneyline odds shift constantly with betting volume and news; a stale line delivers worse expected value than current market prices, so always confirm odds right before betting. Use How to Calculate a Moneyline Payout Before You Bet to verify the exact return on any line you're considering.
Does this apply in every state?
Only where online sports betting is legal — currently 38+ states and Washington D.C. States like California, Texas, and Florida do not have legal online moneyline markets as of 2025. Always confirm local laws before wagering. And one more thing: winning bets have tax implications. See Moneyline Betting Taxes: What US Bettors Owe the IRS for what to track.
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