Confidence Interval Calculator

Calculate confidence intervals for means and proportions

Choose whether to calculate CI for a population mean or a proportion.

Results

Point Estimate
Critical Value
Margin of Error
Lower Bound
Upper Bound
Standard Error
Mean CI: x-bar +/- z*(s/sqrt(n)) or t*(s/sqrt(n))
Proportion CI: p-hat +/- z*sqrt(p*(1-p)/n)