Odds converter
One number in four notations — plus the contract price a prediction market would show for it.
Result
- Contract priceWhat a prediction market would charge
- 35.0¢
- Implied probability
- 35.0 %
- Decimal odds
- 2.86
- American odds
- +186
- Fractional odds
- 13/7
- Profit per $1 staked
- $1.86
Bookmaker lines carry a margin, so their implied probabilities sum to more than 100 %. Prediction market prices do not — the fee is charged separately.
The same number, four ways of saying it
A sportsbook quotes +186, a European bookmaker quotes 2.86, a British one quotes 15/8, and a prediction market quotes 35¢. All four describe the same thing: an event with a roughly 35 % implied chance. The notations differ because the industries that produced them differ, not because the maths does.
Prediction markets are the odd one out, and in a useful way. A contract that pays $1 if the event happens and costs 35¢ states the probability directly — no conversion needed, because the price is the probability. That is why the cents column is the one to anchor on when you are comparing a market against a book.
Where the notations stop agreeing
Bookmaker odds are not implied probabilities, because they include the vig: add up the implied probabilities of every outcome at a sportsbook and you will get more than 100 %. The excess is the margin. Prediction market prices across the outcomes of a single market sum to about 100 %, and the venue charges its fee separately and visibly.
That is the comparison that matters when someone tells you a book is offering better odds. It usually is not, once you have removed the margin — and this converter deliberately does not remove it for you, because the number of outcomes needed to do that honestly is not in this form.
Common questions
What does +186 mean?
Positive American odds tell you the profit on a 100 stake: +186 returns 186 profit plus your 100 back. That works out to an implied probability of about 35 %. Negative odds go the other way — −186 means you must stake 186 to win 100, an implied probability of about 65 %.
How do I convert a prediction market price to a probability?
You do not have to. A contract priced at 35¢ that pays $1 implies a 35 % chance. That direct reading is the main practical difference between a prediction market and a bookmaker's line.
Do these odds include fees?
No. This converter maps one notation onto another and nothing else. Prediction market fees are charged separately from the price, and a sportsbook's margin is baked into the line — neither is visible here.
Read more
These calculators do arithmetic on numbers you supply. They are not advice, and nothing here is a recommendation to take a position.