Body mass index from weight and height, metric or imperial, with the WHO adult category and the 18.5 to 24.9 weight range.

Vector dot, cross, norm, angle, projection, unit vector and distance for vectors of up to 100 entries.

Least-squares line or polynomial fit (degree 1 to 6, up to 100 points) with coefficients, R-squared and residuals.

Transpose a matrix (up to 10x10) with trace, symmetry and skew-symmetry flags, and Frobenius and 1-norms.

Solve Ax=b (n up to 10) by Gaussian elimination with partial pivoting; flags singular and ill-conditioned systems.

Inverse of a square matrix (up to 10x10) by Gauss-Jordan, with A*inv(A) residual and a condition number.

Rank, nullity and reduced row echelon form of a matrix (up to 10x10) with pivot columns.

Compose 2D or 3D rotate, scale and translate steps into one homogeneous matrix, optionally applied to a point.

Multiply two matrices (up to 10x10) given as JSON, with shape check and the product matrix.

Pearson and Spearman correlation of two lists with p-values, plus the least-squares line, R squared and an optional prediction.

Greatest common divisor, least common multiple, Bezout coefficients and modular inverse for integers of any size.

Probability density or mass, cumulative probability and quantiles for normal, binomial, Poisson and Student t distributions.

A/B conversion test: rates, relative lift, two-proportion z-test p-value, confidence interval and a significance verdict.

Exact counts: factorial, combinations, permutations, with repetition, derangements and Catalan numbers, as big integers.

Confidence interval for a mean (t interval from a list) or a proportion (Wilson and Wald from successes and trials).

Frequency in Hz to the nearest note, MIDI number and offset in cents; adjustable A4 reference; tuner-style result.

Spell a chord from its symbol (Cmaj7, F#m7b5, G7b9, Dsus4, C/E): notes, intervals, semitones and MIDI numbers.

BPM to milliseconds for note values, dotted and triplet delay times; or average tap intervals into a steady BPM.

Roman numeral analysis of a chord progression in a key: numerals, inversions, borrowed chords, secondary dominants.

Welch two-sample or one-sample t-test: t statistic, degrees of freedom, p-value, confidence interval and Cohen's d.