Article updated on March 01, 2018

The CONFIDENCE function calculates the confidence interval for a population mean, using a normal distribution.

Formula in cell B6:


Excel Function Syntax

CONFIDENCE(alpha, standard_dev, size)


alpha Required. The significance level used to calculate the confidence level. 0.05 represents a 95% confidence level.
standard_dev Required. The standard deviation for the data points.
size Required. The number of data points.


The CONFIDENCE function returns an #VALUE! error if an argument is not a number.

The CONFIDENCE function returns an #NUM! if alpha is less than 0 (zero) or more than 1.