Normal Distribution Probability Calculator
Calculate probabilities for normal distribution
About this calculator
The Normal Distribution Probability Calculator helps you find probabilities and percentiles for normally distributed data using the bell curve model. This statistical tool is essential for researchers, students, and professionals who need to calculate the likelihood of values falling within specific ranges. Whether you're analyzing test scores, quality control measurements, or any dataset that follows a normal distribution, this calculator provides accurate probability calculations for hypothesis testing, confidence intervals, and statistical analysis.
How to use
Enter the mean (average) and standard deviation of your normal distribution. Input the value or range of values you want to analyze. Select whether you need the probability of a single value, between two values, or in the tails. Click calculate to get your probability result along with a visual representation of the distribution.
Frequently asked questions
What is a normal distribution?
A normal distribution is a bell-shaped probability curve where data clusters around the mean, with 68% within one standard deviation and 95% within two standard deviations.
How do I find the probability between two values?
Enter your distribution parameters, then input both lower and upper boundary values. The calculator will compute the area under the curve between these points.
Can this calculator find percentiles and z-scores?
Yes, the calculator can convert between raw scores, z-scores, and percentiles, making it useful for standardized test interpretation and statistical analysis.