Convert odds

Translate decimal, fractional, and American betting odds into one another and into break-even probability.

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ToolOdds Converter
Input
Output
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Preview

How it works

Decimal odds map to probability as 1 ÷ decimal; fractional a/b becomes 1 + a/b; positive American odds become 1 + odds/100, while negative values become 1 + 100/|odds|. A continued-fraction approximation produces a readable fraction with denominator at most 1,000.

  • Decimal form is the internal representation.
  • The percentage excludes margin, commission, stake limits, and tax.

Worked example

Decimal odds of 2.50
Converted to fractional, American and an implied probability
Input
											Format: decimal
Value: 2.5
Output
												Decimal odds: 2.5
Fractional odds: 3/2
American odds: +150
Implied probability percent: 40

When to use this

Betting comparisons change fractional quotes to decimal, market sheets compare American lines, and break-even checks turn price into required win probability.

Edge cases

  • Decimal odds below 1 are rejected because total return cannot be less than the stake under this convention.
  • American odds of zero are invalid and cannot select either positive or negative formula.
  • Implied probabilities from every outcome can sum above 100% because bookmaker margin is not removed.