How can fractional odds be quickly converted into decimal odds? How can American odds be converted into decimal odds?

Fractional odds (Fractional odds)

• Where they are popular: Great Britain and Ireland.

• Format: Expressed as fractions, e.g. 5/2 or 10/1.

• How they work: The first number shows how much you win when you bet an amount equal to the second number. For example, odds of 5/2 mean that for every 2 units staked, you receive 5 units in winnings. If you bet 2 dollars at odds of 5/2 and the bet wins, you receive 5 dollars in winnings plus your 2-dollar stake back, for a total of 7 dollars.

Decimal odds (Decimal odds)

• Where they are popular: Europe, Russia, Canada, Australia, New Zealand.
• Format: Represented as decimal numbers, such as 1,50, 2,75 or 10,00.
• How they work: To calculate the total payout (including the stake), multiply the stake by the decimal odds. For example, odds of 2,75 mean that a 10-dollar stake produces a payout of 10 × 2,75 = 27,5 dollars (17,5 dollars in winnings and a 10-dollar stake return).

American odds (Moneyline odds)

• Where they are popular: USA.
• Format: Represented with positive or negative numbers, e.g. +150 or -200.
• How they work:
• Negative odds: Show how much you need to bet to win 100 dollars. For example, odds of -200 mean that you need to bet 200 dollars to receive 100 dollars in winnings. The total payout is 300 dollars (100 dollars in winnings plus a 200-dollar stake).
• Positive odds: Show how much you win when you bet 100 dollars. For example, odds of +150 mean that a 100-dollar stake produces 150 dollars in winnings. The total payout is 250 dollars (150 dollars in winnings plus a 100-dollar stake).

Comparison example

• Fractional odds of 2/1 mean that you receive 2 dollars in winnings for every dollar staked.
• Decimal odds of 3,00 mean that the total payout is three times the stake (2 dollars in winnings for every dollar staked).
• American odds of +200 mean that a 100-dollar stake produces 200 dollars in winnings.

Comparison for a single outcome:

• Fractional odds: 2/1.
• Decimal odds: 3,00.
• American odds: +200.
  All three systems show the same thing – a doubling of the stake when winning, but with different calculation and presentation approaches.

Formula for converting odds

Decimal odds = fractional odds + 1,
where the fractional odds are written as a fraction A/B, where:

• A is the numerator,
• B is the denominator.

Example: If the fractional odds are 5/2, the decimal odds are:
Decimal odds = 5/2 + 1 = 2,5 + 1 = 3,5.

Converting American odds to decimal odds

There are two formulas, depending on whether the American odds are positive or negative.

• If the American odds are positive (+X):
  Decimal odds = 1 + X/100
  Example: American odds +150:
  Decimal odds = 1 + 150/100 = 1 + 1,5 = 2,5.

• If the American odds are negative (−X):
  Decimal odds = 1 + 100/X
  Example: American odds −200:
  Decimal odds = 1 + 100/200 = 1 + 0,5 = 1,5.

Summary

• For fractional odds, add 1 to the result of the fraction.

• For positive American odds, divide by 100 and add 1.

• For negative American odds, divide 100 by the absolute value of the odds and add 1.