Odds calculator
Convert odds, find the implied or break-even probability of a price, work out expected value from a probability you supply, and measure the hold in a market. It is arithmetic on the numbers you type: it does not pick a side, and it cannot tell you whether a probability is right.
Odds converter
Type a price in any format and see it in the others, with the probability it implies. Implied probability includes the book’s margin, so it is the number the price asks you to beat, not a fair chance.
- American
- −110
- Decimal
- 1.909
- Fractional
- 10/11
- Implied probability
- 52.38%
An American price worked out from a decimal, fractional or probability input is rounded to a whole number.
Break-even probability
The share of bets at this price that have to win for you to come out even over many bets. Win less often than this and you lose money on average; win more often and you gain, which is why the price matters as much as the pick.
- Break-even probability
- 52.38%
- Decimal price
- 1.909
- Profit on a 1 unit win
- 0.909u
Expected value
Expected value is the average result per unit staked if your probability were exactly right and you could place the same bet many times. The probability is the one you enter: this calculator has no view on it, and a different estimate gives a different answer.
- Expected value per 1 unit
- +0.050u (+5.00% of the stake)
- Break-even at this price
- 52.38%
- Your probability minus break-even
- +2.62%
An average over many bets is not a result for one bet: a single bet at positive expected value still loses often. Nothing here says your probability is right.
Hold and vig
Enter both sides of one market, such as the over and the under. The two implied probabilities add up to more than 100%; the extra is the book’s margin (hold). Removing it in proportion gives a no-vig price for each side.
- Hold (the book's margin)
- 4.55%
- Overround
- 4.76%
- Side A no-vig
- 50.00% (+100)
- Side B no-vig
- 50.00% (+100)
- Implied probabilities, summed
- 104.76%
Hold is the margin as a share of the total (1 − 1/sum). Overround is how far the sum of the implied probabilities sits above 100% (sum − 1).
The proportional split is one common way to remove the margin. Books can place their margin unevenly, so a no-vig price is an estimate of the fair price, not a quote you can take.
New to props?
Start with what a prop bet is and how a line and a price work. For how our projections are made and graded, read the methodology. See what a price looks like on a real slate in NBA, NFL and MLB props, or look a player up in the Explorer. Terms such as vig and push are in the glossary. To strip the vig from both sides of a market, use the no-vig odds calculator.