Statistics & Probability

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Moneyline Odds Calculator.

Convert American moneyline odds to decimal odds and implied probability.

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Set your values

Results update as you type.

decimalOdds: 2.5

decimalOdds

2.500000
impliedProbability: 0.4

impliedProbability

0.400000
impliedProbabilityPercent: 40

impliedProbabilityPercent

40.000000

Results update automatically as you type.

Use Cases

Evaluate Betting Value

Use the implied probability to compare with your own estimate of the event's likelihood. If your estimate is higher, the bet may offer value.

Example: If odds are +150, implied probability is 40%. If you believe the true chance is 50%, the bet has value.

Understand Betting Odds

Quickly convert American odds to a percentage to grasp the market's view of an event's likelihood, helping you make informed decisions.

Example: Convert -200 odds to see a 66.7% implied probability.

Frequently Asked Questions

How do I convert American moneyline odds to implied probability?
Enter the American odds (e.g., +150 or -200) into the calculator. It will compute the implied probability: for positive odds, probability = 100 / (odds + 100); for negative odds, probability = -odds / (-odds + 100). The result shows the percentage chance the market implies.
What do positive and negative moneyline odds mean?
Positive odds (e.g., +200) show how much profit you'd make on a $100 bet, and they indicate an underdog. Negative odds (e.g., -150) show how much you need to bet to win $100, and they indicate a favorite. The calculator handles both.
Why is implied probability different from actual probability?
Implied probability is derived from the odds and includes the bookmaker's margin (vig). It represents the market's assessment, not the true likelihood. The calculator gives you the implied probability, which is useful for comparing odds and identifying value.

Tips & Common Mistakes

Tips

  • Remember that implied probability includes the bookmaker's margin, so the sum of probabilities for all outcomes in an event will exceed 100%.
  • For positive odds, use the formula: probability = 100 / (odds + 100). For negative odds, use: probability = -odds / (-odds + 100).
  • Use this calculator to compare odds from different bookmakers and spot discrepancies.
  • Always consider that implied probability is not the true probability; it's the market's estimate.

Common Mistakes to Avoid

  • Forgetting to include the plus or minus sign when entering odds. The calculator needs it to determine the correct formula.
  • Misinterpreting the result: a 40% implied probability does not mean the team has a 40% chance of winning; it reflects the odds and margin.
  • Using the calculator for non-betting purposes without understanding that it only converts odds to probability, not vice versa.

Last updated: August 13, 2026