Odds Converter
Convert between decimal, fractional, American and implied probability formats instantly. Enter a value in any field and the rest update automatically.
Common Odds Reference
Click any row to load it into the converter above.
| Decimal | Fractional | American | Probability |
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Understanding Betting Odds Formats
Betting odds serve two purposes: they tell you how much you stand to win on a successful wager, and they reflect the implied probability of an outcome according to the bookmaker. Different regions of the world have settled on different formats for expressing the same underlying information. European bookmakers and most online casinos default to decimal odds, which show the total return per unit staked. UK bookmakers traditionally use fractional odds, which express the profit relative to the stake. North American sportsbooks use American (moneyline) odds, which pivot around a $100 reference point.
The most common source of confusion for new bettors is the difference between odds and probability. Odds of 2.00 (decimal) translate to a 50% implied probability, meaning the bookmaker considers both outcomes equally likely. However, real bookmaker odds always include a margin (also called vigorish or overround), which means the implied probabilities across all outcomes in a market will sum to more than 100%. This margin is how the bookmaker makes money regardless of the result.
Being comfortable converting between formats quickly is a practical skill, especially when comparing prices across bookmakers that use different systems. A line that reads -110 at one sportsbook is the same as 1.91 decimal or 10/11 fractional, but spotting value becomes much easier when you can think in a single format and convert the rest on the fly. This tool handles that arithmetic instantly so you can focus on the analysis rather than the calculations.
Frequently Asked Questions
What are decimal odds?
Decimal odds show the total payout per unit staked including your original bet. For example, decimal odds of 2.50 mean a $10 bet returns $25 total ($15 profit plus your $10 stake).
How do American odds work?
American odds use positive and negative numbers. Positive odds (e.g. +150) show how much profit you win on a $100 stake. Negative odds (e.g. -200) show how much you need to stake to win $100 profit.
What are fractional odds?
Fractional odds show the profit relative to your stake. Odds of 3/1 mean you win $3 profit for every $1 staked. Odds of 1/4 mean you win $1 for every $4 staked.
What is implied probability?
Implied probability converts odds into a percentage reflecting the likelihood of an outcome occurring according to the bookmaker. Lower odds mean higher implied probability. Note that bookmaker margins mean implied probabilities across all outcomes will exceed 100%.