Fractional Odds Calculator
Calculate fractional odds, convert between probability and betting odds formats
Calculate Fractional Odds
Number of favorable outcomes
Number of unfavorable outcomes
Fractional Odds Results
Odds Conversions
Betting Calculator
For informational purposes only. We do not support or recommend any form of betting.
Example: Coin Toss
Fair Coin Flip
Chances for success (heads): 1
Chances against success (tails): 1
Fractional odds: 1/1 (even odds)
Calculation
Odds = Chances Against / Chances For
Odds = 1 / 1 = 1/1
Result: 1/1 or "one to one"
Fractional Odds Tips
Fractional odds show the ratio of losses to wins
5/1 odds mean 5 chances to lose, 1 chance to win
Higher numerator = less likely event
1/1 = even odds (50% probability)
Understanding Fractional Odds
What are Fractional Odds?
Fractional odds represent the chances of losing versus the chances of winning in terms of fractions. They show the ratio of unfavorable outcomes to favorable outcomes.
How to Read Fractional Odds
- •5/1 = "five to one" = 5 chances to lose, 1 chance to win
- •1/2 = "one to two" = 1 chance to lose, 2 chances to win
- •1/1 = "even odds" = equal chances to win or lose
Formula
Fractional Odds = Chances Against Success / Chances For Success
Converting to Probability
Probability = Denominator / (Numerator + Denominator)
Example: 5/1 odds = 1/(5+1) = 1/6 = 16.67%
Common Examples
Dice Roll (Single Number)
5/1 odds (5 ways to lose, 1 way to win)
16.67% probability
Coin Flip
1/1 odds (equal chances)
50% probability
Card Draw (Red from Deck)
1/1 odds (26 red, 26 black)
50% probability