Odds Converter
Convert between American, Decimal, and Fractional odds instantly
Convert Betting Odds
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Understanding Odds Formats
American Odds
The most common format in the US. Positive odds (+150) show how much you win on a $100 bet. Negative odds (-150) show how much you need to bet to win $100.
Example: +150 means bet $100 to win $150 profit (total return $250)
Example: -150 means bet $150 to win $100 profit (total return $250)
Decimal Odds
Popular in Europe, Australia, and Canada. Decimal odds show your total return for every $1 wagered (including your stake).
Example: 2.50 means bet $100 to receive $250 total (including your $100 stake)
Fractional Odds
Traditional in the UK and Ireland, especially for horse racing. Fractional odds show your profit relative to stake.
Example: 3/2 means bet $2 to win $3 profit (total return $5)
Example: 1/2 means bet $2 to win $1 profit (total return $3)
Why Convert Odds?
Different sportsbooks and regions use different odds formats. Converting between them helps you:
Compare odds across different sportsbooks that use different formats
Understand your potential payout regardless of how odds are displayed
Calculate implied probability to determine if a bet has value
Common Odds Conversions
Here's a quick reference for common betting odds across all three formats. For a broader look at the tools we and others build around these conversions, see our OddsJam alternative breakdown.
| American | Decimal | Fractional | Implied Probability |
|---|---|---|---|
| -500 | 1.20 | 1/5 | 83.33% |
| -400 | 1.25 | 1/4 | 80.00% |
| -300 | 1.33 | 1/3 | 75.00% |
| -200 | 1.50 | 1/2 | 66.67% |
| -150 | 1.67 | 2/3 | 60.00% |
| -110 | 1.91 | 10/11 | 52.38% |
| +100 | 2.00 | 1/1 (Evens) | 50.00% |
| +110 | 2.10 | 11/10 | 47.62% |
| +150 | 2.50 | 3/2 | 40.00% |
| +200 | 3.00 | 2/1 | 33.33% |
| +300 | 4.00 | 3/1 | 25.00% |
| +400 | 5.00 | 4/1 | 20.00% |
| +500 | 6.00 | 5/1 | 16.67% |
| +1000 | 11.00 | 10/1 | 9.09% |
Odds Conversion FAQs
Why do American odds use positive and negative numbers?
Positive American odds (+) indicate an underdog and show profit on a $100 bet. Negative odds (-) indicate a favorite and show how much you must bet to win $100. The larger the negative number, the bigger the favorite; the larger the positive number, the bigger the underdog.
How do I convert American odds to decimal manually?
For positive American odds: Decimal = (American / 100) + 1. For negative American odds: Decimal = (100 / |American|) + 1. Example: +150 = (150/100) + 1 = 2.50 decimal. Example: -150 = (100/150) + 1 = 1.67 decimal.
What does implied probability mean?
Implied probability is the probability of an outcome suggested by the betting odds. It is calculated as: Implied Probability = 1 / Decimal Odds × 100. If you believe the true probability is higher than the implied probability, the bet has positive expected value.
Why do not implied probabilities add up to 100% for both sides?
When you add the implied probabilities of all outcomes in a market, the total exceeds 100%. This excess is called the vig, juice, or margin — it is how sportsbooks make money. For example, -110 on both sides of a spread has a combined implied probability of 104.76%, meaning the book has a 4.76% edge.
Which odds format is best?
There is no best format — it is a matter of preference and what you are used to. However, many experienced bettors prefer decimal odds because they make it easy to calculate payouts (just multiply stake × odds) and they are widely used internationally. Decimal odds also make it simple to compare value across different bets.
Odds Conversion Formulas
Converting TO Decimal
From American (+):
Decimal = (American / 100) + 1
From American (-):
Decimal = (100 / |American|) + 1
From Fractional (a/b):
Decimal = (a / b) + 1
Converting FROM Decimal
To American (if Decimal ≥ 2):
American = (Decimal - 1) × 100
To American (if Decimal < 2):
American = -100 / (Decimal - 1)
Implied Probability:
Probability = (1 / Decimal) × 100
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