Advanced Confidence Interval Calculator

Calculate confidence intervals for sample data with this free tool.

Sample Mean (x̄)

The average value of your sample data.

Sample Standard Deviation (s)

Measure of dispersion in your sample.

Sample Size (n)

Number of observations in your sample.

Confidence Level

The probability that the interval contains the true parameter.

About Confidence Intervals

A confidence interval is a range of values, derived from sample statistics, that is likely to contain the value of an unknown population parameter.

If we repeated our sampling many times, approximately % of the calculated confidence intervals would contain the true population mean.

The confidence interval is calculated using:

CI = x̄ ± z*(s/√n)

Where: