Free Proportion Sample Size Calculator - This calculator determines a sample size to select to meet certain criteria related to a confidence percentage, reliability percentage, and a p value proportion. Simply enter your values not using percentage signs. This works whether p^ is known or not known.

Free Sample Size Reliability for μ Calculator - Given a population standard deviation σ, a reliability (confidence) value or percentage, and a variation, this will calculate the sample size necessary to make that test valid.

Free Sample Size Requirement for the Difference of Means Calculator - Given a population standard deviation 1 of σ₁, a population standard deviation 2 of σ₂ a reliability (confidence) value or percentage, and a variation, this will calculate the sample size necessary to make that test valid.