Odds Converter — Decimal, Fractional, American & Implied Probability
Convert between decimal, fractional, American and Malay odds — and implied probability.
Different bookmakers and markets quote odds in different formats. This converter takes any of decimal, fractional, American or Malay and shows all the others, plus the implied probability (the chance the odds represent).
You can also enter an exchange commission to see the effective odds after the cut — handy when comparing a Betfair price against a fixed-odds bookmaker.
How it works
Everything converts through decimal odds. Implied probability is simply one divided by the decimal price; a $4.00 chance implies 25%.
The sum of implied probabilities across a market is the “overround” — it’s why a book adds to more than 100% and the margin the bookmaker builds in.
implied probability = 1 ÷ decimal odds · effective odds = 1 + (odds − 1) × (1 − commission)
Worked example
- Fractional: 5/2
- American: +250
- Implied probability: 28.6%
- With 5% commission: effective $3.375
FAQ
- How do I read decimal odds?
- Decimal odds include your stake: $3.50 returns $3.50 for every $1, i.e. $2.50 profit plus your $1 back.
- What is implied probability?
- The win chance the odds represent — one divided by the decimal price. Compare it to your own estimate to spot value.
- What are effective odds?
- Your real odds after exchange commission is taken from your winnings — useful for comparing exchange and bookmaker prices fairly.
- What is the overround?
- The amount a full market’s implied probabilities exceed 100% — the bookmaker’s built-in margin.
This converts one price. The Bet Tracker records the odds you took on every bet and compares them to the close.
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