Confidence Interval Calculator
Estimate a mean or proportion interval with the appropriate model.
Runs on your device · No input uploadsResult
LOCALEnter your values, then choose Calculate.
How this tool works
Unknown population SD uses Student’s t; a known population SD uses z. Proportions use the Wilson score interval. These assume independent representative observations, with a normal population or adequate approximation for mean intervals. The confidence level describes repeated-sampling coverage.