Math Calculators

Confidence Interval Calculator

Calculate confidence interval for a population mean using z critical values.

Sample Mean

Standard Deviation

Sample Size (n)

Confidence Level

ErrorStandard deviation and sample size must be > 0

Confidence Interval Formula

CI = x̄ ± z × (σ/√n)

x̄=50, σ=10, n=100, 95% CI: 50 ± 1.96×1 = [48.04, 51.96].

When should I use t instead of z?

Estimate required sample size for a population proportion with chosen confidence and margin of error.

Calculate z-score from value, mean, and standard deviation.

Calculate standard deviation, variance, and mean for a data set. Enter comma-separated values for statistical analysis.