Free Confidence Interval Calculator 2025 | Thiyagai.com

Confidence Interval Calculator

Calculate the confidence interval for your sample data with statistical precision

About Confidence Intervals

A confidence interval gives an estimated range of values which is likely to include an unknown population parameter. The width of the confidence interval gives us some idea about how uncertain we are about the unknown parameter.

This calculator uses the normal distribution (Z-distribution) to calculate the confidence interval for a population mean when the population standard deviation is known.