Odds Converter

Betting Odds Converter: Decimal, Fractional & American

Understanding odds formats is one of the most fundamental skills in sports betting. Whether you're comparing lines across bookmakers or calculating your potential payout, knowing how to convert between decimal, fractional, and American (moneyline) odds is essential. Our free converter does the math instantly.

Why Do Different Odds Formats Exist?

Different regions of the world adopted their own systems for expressing probability and payouts:

• Decimal Odds (European): Used across Europe, Australia, and Canada. The number represents your total return per unit staked, including your original bet. Example: odds of 2.50 mean a €10 bet returns €25 (€15 profit + €10 stake).
• Fractional Odds (British): Traditional format in the UK and Ireland. Expressed as a fraction (e.g., 3/1 or "three to one"), showing how much profit you win relative to your stake. A £10 bet at 3/1 wins £30 profit plus your £10 back.
• American Odds (Moneyline): Standard in the United States. Positive numbers (+200) show how much you win on a $100 stake. Negative numbers (-150) show how much you need to stake to win $100.

How to Convert Between Odds Formats

While our tool does this automatically, understanding the formulas helps you think about odds more intuitively:

Decimal to Fractional

Subtract 1 from the decimal odds, then express as a fraction. Example: 3.00 → 3.00 - 1 = 2/1.

Decimal to American

If decimal odds are 2.00 or higher: American = (Decimal - 1) × 100. Example: 2.50 → +150.
If decimal odds are below 2.00: American = -100 / (Decimal - 1). Example: 1.50 → -200.

Fractional to Decimal

Divide the fraction and add 1. Example: 5/2 → (5 ÷ 2) + 1 = 3.50.

Understanding Implied Probability

Every set of odds implies a probability of that outcome occurring. This is critical for finding value bets — situations where you believe the true probability is higher than what the odds suggest.

The formula is simple: Implied Probability = 1 / Decimal Odds × 100.

• Odds of 2.00 = 50% implied probability
• Odds of 3.00 = 33.3% implied probability
• Odds of 1.50 = 66.7% implied probability

If you think a team has a 60% chance of winning but the bookmaker's odds imply only 50%, that's a value bet worth considering.

Why Comparing Odds Across Bookmakers Matters

Different bookmakers often offer slightly different odds on the same event. Over hundreds of bets, always taking the best available price compounds into significantly higher returns. This practice — known as line shopping — is one of the simplest ways to improve your long-term profitability.

Use our converter to quickly standardize odds from different bookmakers into a single format, making comparison effortless.

FAQs

Which odds format is the easiest to understand?

Decimal odds are widely considered the most intuitive because the number directly represents your total return. If you see 2.50, you know a €1 bet returns €2.50. No extra calculation needed.

What does "even money" mean?

Even money means the payout equals your stake — you double your money if you win. It's expressed as 2.00 (decimal), 1/1 or "evens" (fractional), or +100 (American). The implied probability is exactly 50%.

Why are odds different at different bookmakers?

Each bookmaker sets odds based on their own risk models, market exposure, and margin strategy. These differences create opportunities for bettors to find better value by comparing prices before placing a bet.

What is the bookmaker's margin (overround)?

The margin is how bookmakers guarantee profit. If you add up the implied probabilities of all outcomes in a market, they'll total more than 100% — the excess is the bookmaker's margin. Lower margins mean better odds for you. Typical margins range from 2-5% for major markets.