Probability from odds Calculator

Free probability from odds calculator to calculate probability from odds. Instant results in your browser — no signup.

JavaScript is required for live calculation.

You can still read how Probability from odds Calculator works, the formula, examples, and FAQs below.

Odds format
Decimal odds
For (wins)
Against (losses)

Direct calculator

Inputs

Odds format

Decimal odds

For (wins)

Against (losses)

Results update when you click Calculate.

Implied probability

25.00%

p = 1 / 4.00

Decimal p

0.2500

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What this result means

Free probability from odds calculator to calculate probability from odds. Instant results in your browser — no signup. From decimal odds D: p = 1/D. From a:b odds: p = a/(a+b).

Assumptions

Rule dependency: Universal formula.

How is it calculated?

From decimal odds D: p = 1/D. From a:b odds: p = a/(a+b).

Example

Decimal 4.00 → 25% implied probability.

Frequently asked questions

Bookmaker margin?+

Real books sum above 100% — this is fair implied probability.