Compute sample and population covariance, bivariate co-movement, and Pearson correlation r.
Correlation Coefficient Calculator – Free Pearson’s r & R² Estimator
Calculate Pearson’s correlation coefficient (r) and R² explained variance.
Confusion Matrix, Precision, Recall & F1-Score Calculator
Calculate Precision, Recall, Specificity, F1-Score, Balanced Accuracy, Matthews Correlation Coefficient (MCC), and Youden
Confidence Level Calculator — Margin of Error & Confidence Intervals
Free confidence level calculator. Calculate confidence intervals (90%, 95%, 99%), margin of error (MOE), standard error, and critical z-scores for sample data.
Confidence Interval Calculator – Free Mean & Proportion Margin of Error
Calculate confidence intervals and margins of error for sample means and proportions.
Complex Number Converter | Rectangular to Polar & Euler Form
Convert complex numbers between Cartesian form (a + bi), Polar form (r∠θ), and Euler exponential form (re^(iθ)).
Complex Number Calculator | Arithmetic, Conjugate & Modulus
Perform complex arithmetic (addition, subtraction, multiplication, division, powers) with modulus and complex conjugate.
Cohen’s d Calculator – Effect Size, Hedges’ g & Glass’s Delta
Calculate Cohen's d effect size online. Features pooled standard deviation, Hedges' g correction, Glass's delta, common language effect size, and overlap metrics.
Coefficient of Variation Calculator – Relative Standard Deviation (RSD)
Calculate Relative Standard Deviation (RSD %) and normalize risk dispersion across datasets.
Circle Equation Calculator – Standard & General Form Solver
Convert and solve circle equations between standard form (x-h)² + (y-k)² = r² and general form with center and radius.