Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Normal Distribution Calculator

Convert any raw value to a z-score using a custom mean and standard deviation, then find corresponding normal distribution probabilities. Perfect for standardizing test scores, measurements, or survey results.

X Value

Mean (μ)

Standard Deviation (σ)

Fill in the required fields to see your result.

Statistics

Confidence Interval Calculator

Compute the margin of error around a sample mean for a 90%, 95%, or 99% confidence interval using the z-distribution. The half-width of the CI tells you how precisely your sample estimates the population mean — essential for survey reporting, scientific publication, and any inference.

Sample Size (n)

Standard Deviation

Confidence Level

Fill in the required fields to see your result.

Key differences

	Normal Distribution Calculator	Confidence Interval Calculator
Category	Statistics	Statistics
Inputs required	3	3
Result	Z-Score	Margin of Error (±)
What it does	Convert any raw value to a z-score using a custom mean and standard deviation, then find corresponding normal distribution probabilities. Perfect for standardizing test scores, measurements, or survey results.	Compute the margin of error around a sample mean for a 90%, 95%, or 99% confidence interval using the z-distribution. The half-width of the CI tells you how precisely your sample estimates the population mean — essential for survey reporting, scientific publication, and any inference.