Accuracy Calculator
Calculate accuracy, precision, recall, F1, MCC from a confusion matrix. Also computes measurement error metrics (MAE, RMSE, MAPE) and simple proportion accuracy with confidence intervals.
Free Sampling Calculators
8 toolsSample size, margin of error, standard error, and accuracy calculators. Browse our free sampling tools below — no sign-up required.
Constant of Proportionality Calculator
Find the constant of proportionality k from data pairs. Supports direct, inverse, squared, square root, and custom power models with R², residuals, and fit analysis.
Margin of Error Calculator
Calculate margin of error from sample data or find required sample size for a desired MOE. Supports proportions and means with finite population correction.
Sampling Distribution of Sample Proportion Calculator
Explore the sampling distribution of p̂. Calculate mean, standard error, probabilities, and quantiles. Visualize the bell curve with normal approximation conditions.
Sampling Error Calculator
Calculate sampling error (standard error and margin of error) for proportions and means. Includes finite population correction, error decomposition, and sample size comparison.
Sensitivity & Specificity Calculator
Calculate sensitivity, specificity, PPV, NPV, likelihood ratios, and Youden's J from a confusion matrix. Includes PPV/NPV table at different prevalence levels.
Specificity Calculator
Calculate specificity (true negative rate) from TP, FP, FN, TN. Includes false positive rate, confidence interval, prevalence-adjusted PPV table, and diagnostic metrics.
Standard Error Calculator
Calculate standard error for means, proportions, differences, or raw data. Includes margin of error, finite population correction, and SE vs sample size comparison.