SportCalc.

Betting Odds Converter

Convert any odds format to the others and reveal the implied probability behind the price.

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How to use the betting odds converter

  1. Pick the format of the odds you have.
  2. Type the odds value.
  3. See the equivalent decimal, fractional, American odds and implied probability instantly.

Implied probability and the bookmaker margin

Implied probability is what the odds say about an outcome's likelihood. Because a bookmaker's implied probabilities across all outcomes sum to more than 100%, that excess — the overround or vig — represents their built-in margin.

Frequently asked questions

How do you convert decimal odds to probability?

Implied probability = 1 ÷ decimal odds. Decimal odds of 2.50 imply a 40% chance (1 ÷ 2.50 = 0.40).

What's the difference between fractional and American odds?

Fractional odds (e.g. 5/2) are common in the UK and show profit relative to stake. American odds use + for underdogs and − for favourites relative to a 100-unit stake.

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