What this calculator does
Convert probability to odds for and against, or convert entered odds to probability.
How it works
The calculator evaluates for odds A:B, probability = A ÷ (A + B); odds against interchange success and failure. Inputs are checked before calculation, and invalid values such as zero denominators or out-of-range selections produce a clear error instead of a misleading result.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
4-
?mode=Input typeChoice · Required · Default: oddsFor · Accepted values: oddsFor, oddsAgainst, probability
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?a=ANumber · Required · Default: 3
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?b=BNumber · Required · Default: 2
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?probability=Probability of winning (%)Number · Required · Default: 60
Outputs
4-
winProbabilityWinning probabilityPercentage · Primary output
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loseProbabilityLosing probabilityPercentage
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oddsForOdds forText
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oddsAgainstOdds againstText
Inputs and results
The inputs are Input type, A, B, Probability of winning (%). Results include Winning probability, Losing probability, Odds for, Odds against.