Which odds formats can I convert?

This converter supports fractional, decimal, American (moneyline) and implied probability. Enter any format to update the others.

What is implied probability?

Implied probability is the win percentage represented by the odds. It is calculated as 1 divided by decimal odds.

Why does the fractional output look rounded?

Fractional odds are approximated using a maximum denominator to keep the output readable while staying close to the true decimal odds.

Odds Converter for Decimal, Fractional, and American Lines

Convert odds instantly between fractional, decimal and American (moneyline), with implied probability shown automatically.

Convert fractional ↔ decimal ↔ American in real time.
See implied probability for any format.
Useful for Betfair, Matchbook, Smarkets and bookmaker pricing.

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Odds Converter

Enter odds in any format — the others update automatically.

Odds formats

Use this odds converter to flip between exchange-friendly decimal odds, traditional fractional prices and American moneyline quotes. Implied probability updates instantly so you can spot the market expectation at a glance.

How it works

How the conversion works

Fractional → Decimal: Decimal = 1 + (a ÷ b)
American → Decimal: Decimal = 1 + (value ÷ 100) for positive, 1 + (100 ÷ |value|) for negative.
Probability → Decimal: Decimal = 1 ÷ p where p is the implied probability as a decimal.
Decimal → Probability: Probability % = (1 ÷ Decimal) × 100

Rounding: Decimal odds show 2 dp, moneyline rounds to the nearest whole number, and fractional odds are simplified with a max denominator of 200.

Always gamble responsibly. This calculator is for information only and does not guarantee profit.

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