Statistics Calculators
Mean, probability, distributions, hypothesis testing and more.
Birthday Paradox Calculator
Enter the number of people to find the probability that at least two share a birthday. 23 people already exceeds 50%, 50 people reach 97%!
Bayes' Theorem Calculator
Enter P(A), P(B) and P(B|A) to compute the posterior probability P(A|B). Essential for medical testing, spam filtering and decision analysis.
Confidence Interval Calculator
Enter sample mean, standard deviation, size and confidence level to get the confidence interval, margin of error and standard error. For statistical analysis and surveys.
Standard Deviation Calculator
Enter a set of numbers (up to 8) to compute the mean, variance and standard deviation (population/sample), measuring data dispersion.
Mean (Average) Calculator
Compute the arithmetic mean from a number series.
Interquartile Range (IQR) Calculator
Compute Q1, Q3 and the IQR from a number series.
Mean Absolute Deviation (MAD) Calculator
Compute the mean absolute deviation from a number series.
Linear Regression Calculator
Compute the regression slope and intercept from data points.
Correlation Coefficient Calculator
Compute Pearson's r from paired data.
Standard Error Calculator
Compute the standard error SE = σ/√n from a standard deviation and sample size.
Normal Distribution Calculator
Compute cumulative P(X≤x) and right-tail P(X>x) for a normal distribution.
Binomial Distribution Calculator
Compute P(X=k) and cumulative probability for a binomial distribution.