What are the odds?
The odds are usually presented as a ratio. For example, the odds of your favorite football team losing a match may be 1 to 5. The odds of you winning a lottery might be 1 to 10,000. On the other hand, the odds of the horse you bet on winning the race may be equal to 4 to 3.
There are two types of odds ratios: odds of winning and odds of losing. For odds of winning, the first number is the chances for success, and the second is the chances against success (of losing). For odds of losing, the order of these numbers is switched.
How to calculate odds
Our betting odds calculator takes a step further and calculates the percentage probability of winning and losing. If your odds are 5 to 1, the team would win 5 out of 6 games and lose 1 of them. By converting fraction to percent, we can say that the chances of winning are 5/6 ≈ 83.33%, and of losing 1/6 ≈ 16.67%.
The formulas used:
- Probability of winning = chances for success / all chances
- Probability of losing = chances against success / all chances
- All chances = chances for success + chances against success
Odds formats explained
Our calculator automatically converts between the three major odds formats used worldwide:
- Fractional (UK) odds — shown as a fraction like 5/12. The numerator represents your profit and the denominator represents your stake. Example: 5/12 means you win $5 for every $12 you bet.
- Decimal (European) odds — a single number like 2.4167. Multiply your stake by this number to get the total payout (including the original stake). Common in Europe, Australia, and Canada.
- American (Moneyline) odds — shown as +150 or −200. A positive number shows how much profit a $100 bet returns; a negative number shows how much you must bet to win $100. Used primarily in the United States.
How to use the odds ratio calculator: an example
- Find out what the odds are expressed as a ratio. Let's say that the odds of you winning in a school lottery are 5 to 12.
- Enter 5 in the "Chances for success" field and 12 in the "Chances against success" field.
- Sum up all of the chances: 5 + 12 = 17.
- The calculator gives you: probability of winning = 5/17 ≈ 29.41%.
- Probability of losing = 12/17 ≈ 70.59%.
- Optionally, enter a bet amount and select your currency to see potential winnings and total payout.
Bet payout calculation
If you enter a bet amount, the calculator will show you:
- Potential winnings = bet amount × (chances for / chances against)
- Total payout = bet amount + potential winnings
Supported currencies include USD, EUR, GBP, JPY, CAD, AUD, CHF, CNY, INR, BRL, MXN, RUB, and more.
FAQs
What are one to five odds of losing?
If the odds for a football team losing are 1 to 5, it means that there are five chances of them winning and only 1 of them losing. That means that if they played six times, they would win five times and lose once.
How do I convert odds to probability?
To calculate probability given odds, first you need to know if the odds are in favor or against:
- If x : y are odds in favor, then:
probability = x / (x + y) - If x : y are odds against, then:
probability = y / (y + x)
Example: If odds are 4:1 in favor, then probability is 4 / (4 + 1) = 4/5 = 80%.
What is the difference between decimal and American odds?
Decimal odds are common in Europe and Australia — they represent total return per unit staked (including stake). American (Moneyline) odds are used in the United States — positive odds (+150) show profit per $100 bet, while negative odds (−200) show how much you must bet to win $100.
How do I convert fractional odds to decimal?
To convert fractional odds (e.g., 5/2) to decimal odds, divide the numerator by the denominator and add 1: decimal = (5/2) + 1 = 2.5 + 1 = 3.5.