Confidence Interval Calculator
Calculate confidence intervals for means, proportions, and differences with statistical analysis
Data Input
Results
Enter your data and click Calculate to see the confidence interval
Confidence Interval Guide
Interpretation
• Confidence level = certainty
• CI contains true parameter
• Narrower CI = more precise
• Higher confidence = wider CI
When to Use
• Estimate population parameters
• Compare groups
• Assess precision
• Make decisions
Assumptions
• Random sampling
• Normal distribution
• Independent observations
• Adequate sample size
Tips
- Enter the dimensions in the same unit for consistency.
- Results update automatically as you type.
- Use the unit selector to convert between different measurement systems.