Statistical Calculators
Sample size and power, calculated correctly.
138 free, browser-based calculators covering the methods used in clinical trial design — from a simple two-sample t-test to adaptive group sequential designs. Every result runs client-side and every formula is documented and referenced.
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Means: One and Two Groups
One- and two-sample t-tests, z-tests, and confidence intervals for comparing group means.
Browse → 02 · 9 calculatorsMeans: Correlated, Paired, and Cross-Over Designs
Paired t-tests, 2x2 and higher-order crossover designs, and bioequivalence.
Browse → 03 · 9 calculatorsMeans: Many Groups (ANOVA)
One-way and two-way ANOVA, repeated measures, contrasts, and Dunnett's test.
Browse → 04 · 12 calculatorsProportions: One and Two Groups
One- and two-sample tests, confidence intervals, and non-inferiority for proportions.
Browse → 05 · 5 calculatorsProportions: Correlated and Paired
McNemar's test, paired proportions, and other matched binary-outcome designs.
Browse → 06 · 4 calculatorsProportions: Many Groups
Chi-square tests, trend tests, and R×C contingency table designs.
Browse → 07 · 12 calculatorsSurvival Analysis
Log-rank tests, Cox regression, competing risks, and time-to-event sample size.
Browse → 08 · 5 calculatorsCounts and Rates
Poisson and negative binomial regression for count and rate outcomes.
Browse → 09 · 10 calculatorsCorrelation and Regression
Pearson and Spearman correlation, linear regression, and logistic regression.
Browse → 10 · 8 calculatorsDiagnostic Accuracy and Agreement
Sensitivity, specificity, ROC curves, and inter-rater agreement statistics.
Browse → 11 · 8 calculatorsNon-Inferiority and Equivalence
TOST equivalence testing, non-inferiority margins, and switching designs.
Browse → 12 · 11 calculatorsGroup Sequential, Adaptive, and Interim Analysis
Interim analyses, alpha-spending functions, and adaptive trial designs.
Browse → 13 · 7 calculatorsDose-Finding and Phase I/II Designs
3+3, CRM, BOIN, and other early-phase dose-escalation designs.
Browse → 14 · 5 calculatorsCluster Randomized and Multi-Level Designs
Cluster-randomized, stepped-wedge, and other multi-level trial designs.
Browse → 15 · 6 calculatorsMixed Models and Longitudinal Data
MMRM, linear mixed models, and other repeated-measures / longitudinal designs.
Browse → 16 · 4 calculatorsMultiplicity and Multiple Testing
Bonferroni correction, gatekeeping procedures, and multiple-endpoint adjustments.
Browse → 17 · 5 calculatorsBayesian Sample Size Methods
Bayesian assurance, credible interval width, and borrowing from historical data.
Browse → 18 · 5 calculatorsVariances and Confidence Intervals
Confidence intervals for standard deviations, variances, and tolerance intervals.
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