used more than 50 million times!

Below you will find descriptions and links to 10 free statistics calculators for computing different statistical confidence intervals.

If you like, you may also use the search page to help you find what you need.

This calculator will compute the 99%, 95%, and 90% confidence intervals for a binomial probability, given the number of successes and the total number of trials. This calculator relies on the Clopper-Pearson (exact) method.

This calculator will compute the 99%, 95%, and 90% confidence intervals for a predicted value of a regression equation, given a predicted value of the dependent variable, the standard error of the estimate, the number of predictors in the model, and the total sample size.

This calculator will compute the 99%, 95%, and 90% confidence intervals for the mean of a normal population, given the sample mean, the sample size, and the sample standard deviation.

This calculator will compute the 99%, 95%, and 90% confidence intervals for the mean of a normal population when the population standard deviation is known, given the sample mean, the sample size, and the population standard deviation.

This calculator will compute the 99%, 95%, and 90% confidence intervals for the f^{2} effect size associated with a multiple regression study, given the f^{2} value, the number of predictors in the model, and the total sample size.

This calculator will compute the 99%, 95%, and 90% confidence intervals for an indirect mediation effect, given the regression coefficient and standard error for the relationship between the independent variable and the mediator, and the regression coefficient and standard error for the relationship between the mediator and the dependent variable.

This calculator will compute the exact 99%, 95%, and 90% confidence intervals for a Poisson mean, given the number of event occurrences.

This calculator will compute the 99%, 95%, and 90% confidence intervals for an R^{2} value (i.e., a squared multiple correlation), given the value of the R-square, the number of predictors in the model, and the total sample size.

This calculator will compute the 99%, 95%, and 90% confidence intervals for a regression coefficient, given the value of the regression coefficient, the standard error of the regression coefficient, the number of predictors in the model, and the total sample size.

This calculator will compute the 99%, 95%, and 90% confidence intervals for a regression intercept (i.e., the regression constant), given the value of the regression intercept, the standard error of the regression intercept, the number of predictors in the model, and the total sample size.