The Odds Converter: Bridging American, Decimal, and Fractional Bets

The calculator below instantly translates any odds format into the other two, including the percentage chance the bookmaker assigns to that bet winning. This transparency is key to finding the best value across different sportsbooks, especially those that use international Decimal or Fractional odds.

Betting Odds Converter Tool

The Three Main Odds Formats Explained

While American sportsbooks primarily use Moneyline odds, understanding the other formats is crucial for competitive betting.

1. American Odds (Moneyline)

This format is centered around winning $100.

• Positive Odds (Underdog, e.g., +200): Shows the profit you will win on a $100 wager.

Example: Odds of +200 mean a $100 bet wins $200 profit (for a total return of $300).

• Negative Odds (Favorite, e.g., -150): Shows the amount you must risk to win $100 profit.

Example: Odds of -150 mean you must bet $150 to win $100 profit (for a total return of $250).

2. Decimal Odds (European)

This is the standard format used across most of Europe and Australia. It is the easiest to calculate payouts, as it shows the total return (profit + stake) for every $1 wagered.

• Example: Odds of 2.50 mean a $10 bet returns $25.00 total ($15.00 profit + $10 stake).
• Note: Any decimal odds below 2.00 indicate a favorite (a less than 50% chance of winning).

3. Fractional Odds (Traditional/UK)

Commonly used in the UK and for horse racing, this format expresses the ratio of profit to stake.

• Example: Odds of 5/2 (read as “five to two”) mean you win $5 profit for every $2 you bet.
• Calculation: If you bet $10 at 5/2, you win $25 profit (($10 / 2) x 5), plus your original $10 stake back.

The Value of Implied Probability

The most critical calculation the converter provides is the Implied Probability. This is the percentage chance that the oddsmaker believes your bet will win, based solely on the odds they set.

• Why it Matters: A sound betting strategy is built on identifying situations where you believe your selection has a higher chance of winning than the bookmaker’s implied probability.

If a bet has +100 American odds, the implied probability is 50%.

If you think the true chance is 60%, you have found value.

How to Convert Odds Manually (For Reference)

While the tool does the heavy lifting, understanding the formulas can improve your betting speed.

American to Decimal Conversion

Decimal to Fractional Conversion

• Formula: Decimal Odds – 1 (The result is the fractional ratio over 1, e.g., 3.00 becomes 2/1).

Example: $1.50$ becomes $1.50-1=0.50$. This is $0.50/1$, which simplifies to 1/2 or $1:2$.

Example: $4.00$ becomes $4.00-1=3.00$. This is $3/1$ or $3:1$.