Calculate the t-statistic (t value) from sample data. Get t score, degrees of freedom (df), and p-value for common t-test setups.

Run a t-test online: one-sample, two-sample (independent), or paired. Get t statistic, degrees of freedom, p-value, and decision instantly.

Find outliers using Tukey’s fences (IQR method). Calculate Q1, Q3, IQR, lower/upper fences, and list mild or extreme outliers fast.

Calculate statistical power or required sample size using effect size, alpha, and test type. Ideal for t-tests and z-tests. Fast & free.

Calculate sample size using confidence level, margin of error, population size, and expected proportion. Perfect for surveys, polls, and research.

Calculate margin of error using sample size, confidence level, and proportion (p). Ideal for surveys, polls, and confidence intervals.

Calculate percentiles from any dataset. Find the percentile value (e.g., 90th) or percentile rank of a score. Fast, free, and accurate.

Calculate sample or population variance from any dataset. Get instant results with clear step-by-step output.

Calculate interquartile range (IQR) quickly. Get Q1, median, Q3, IQR, and the 5-number summary from your dataset instantly.