#030 · Odds Formats & Market Comparison Tool

Fractional Odds Converter

Convert fractional odds into decimal odds, American odds, implied probability, and an optional stake return.

Calculator

Enter values
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How to use this betting tool

  1. Enter the requested values using the units shown.
  2. Check that every quoted price and probability belongs to the same scenario.
  3. Select Calculate and review both the headline result and its stated assumption.

What this tool calculates

Convert fractional odds into decimal odds, American odds, implied probability, and an optional stake return.

Decimal odds = numerator ÷ denominator + 1. Implied probability = denominator ÷ (numerator + denominator) × 100.

Results are informational. Actual settlement can vary by operator rules and jurisdiction.

Worked example

Fractional odds 3/2 convert to decimal 2.50, American +150, and 40.00% implied probability. A $100 stake returns $250.

ExampleFractional odds 3/2 convert to decimal 2.50, American +150, and 40.00% implied probability. A $100 stake returns $250.

Tips and limitations

  • Use prices from the same market and point in time.
  • Do not round inputs before calculating.
  • Confirm void, push, commission and deduction rules with the operator.

FAQ

Which odds format does the Fractional Odds Converter use?

All odds inputs on this page use decimal odds unless the field explicitly asks for a probability or fractional numerator and denominator.

Are displayed values rounded during the calculation?

No. The calculator keeps full JavaScript numeric precision internally and rounds only the values shown on screen.

Can bookmaker settlement rules change the result?

Yes. Voids, pushes, deductions, dead heats, commissions and market-specific rules can change an actual settlement.

Does this calculator use live bookmaker or match data?

No. It calculates only from the values entered in this browser and does not connect to a bookmaker or sports feed.

Should this result be treated as a betting recommendation?

No. It is a transparent arithmetic or model estimate for comparison, not a prediction or recommendation.

Calculation reference

FormulaDecimal odds = numerator ÷ denominator + 1. Implied probability = denominator ÷ (numerator + denominator) × 100.
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