Odds Ratio Calculator
Enter the 2 × 2 table counts
Group
Outcome +
Outcome −
Exposed / Group 1
Unexposed / Group 2
95%
Reference direction
Compares Group 1 odds with Group 2 odds. OR > 1 indicates higher odds in Group 1.
Enter non-negative whole-number counts.
Results
Odds ratio
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Group 1 vs Group 2
95% confidence interval
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Log-scale Wald / Taylor interval
Two-sided Wald p
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H₀: OR = 1
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Odds ratio and confidence interval
Observed outcome proportion
Risk ratio
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Risk difference
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Fisher exact p
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Minimum expected count
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How this is calculated
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The primary estimate is the 2 × 2 cross-product odds ratio. Its confidence interval and Wald test use the approximately normal distribution of ln(OR). Fisher’s exact test is also reported from the original integer counts and is especially useful when expected cell counts are small. An odds ratio describes association, not causation.
