Featured contributor MSc Applied Statistics; 7 years in analytics and data tooling.

Daniel Oh

Senior Contributor, Math & Statistics

0 calculators 0 articles Member since Jun 2026

About

Daniel writes and reviews the math and statistics calculators. His explainers lean on worked examples, clean formulas, and obvious edge cases so readers can copy the logic straight into a spreadsheet.

He previously worked as a data scientist at a consumer-tech startup before moving into full-time writing and tooling.

Areas of expertise

Statistics Probability Percentages Data analysis

Education & credentials

BSc Mathematics — University of Toronto
MSc Applied Statistics — ETH Zürich

Physics

Beam Second Moment of Area (I) Calculator

Calculates second moment of area (moment of inertia), section modulus, and radius of gyration for rectangular and I-sect...

basic

15,752 4.8 1 min

Finance

Piotroski F-Score Financial Strength Calculator

Compute the Piotroski F-Score (0-9), a single-page screen for fundamental strength of a value stock. Nine binary 1-or-0...

basic

2,441 4.7 1 min

Biology / Genetics

Allele Frequency Calculator

Compute the frequency of two alleles in a population from observed counts of homozygous-dominant, heterozygous, and homo...

basic

7,723 4.1 1 min

Biology / Microbiology

Bacterial Growth Calculator

Project bacterial population size from an initial cell count, the generation (doubling) time, and elapsed time.

basic

6,385 3.9 1 min

Other

Final Grade Calculator

Find the percentage you need to score on the final exam to finish a course with a target overall grade.

basic

10,830 4.4 1 min

Math / Geometry

Area of a Circle Calculator

Compute the area, circumference, and diameter of a circle from any single input.

basic

13,103 4.9 1 min

Physics

Moody Chart Friction Factor from Reynolds Number and Roughness Calculator

Approximates the Darcy–Weisbach friction factor using the Colebrook–White equation (Churchill approximation): 1/√f = −2·...

basic

3,932 4.2 1 min

Math

Spearman Rank Correlation from Σd² Calculator

Compute the Spearman rank-order correlation coefficient ρ from the sum of squared rank differences and the number of pai...

basic

22,639 4.5 1 min

Math / Geometry

Two-Line 2-D Intersection Calculator

Compute the (x, y) intersection of two lines a₁·x + b₁·y = c₁ and a₂·x + b₂·y = c₂ via the determinant. Returns the uniq...

basic

19,968 4.6 1 min

Math

Vector Projection of a onto b Calculator

Compute the projection of vector a onto vector b in 3-D: proj_b a = (a · b / |b|²) · b. Reports the scalar projection co...

basic

21,945 4.7 1 min

Math

3-D Rodrigues Rotation Matrix Calculator

Compute the nine entries of the 3-D rotation matrix that rotates by angle θ about a unit vector axis (k_x, k_y, k_z), vi...

basic

554 4.5 1 min

Math / Percentage

Complex Number Calculator

Add, subtract, multiply, or divide two complex numbers (a + bi) and (c + di), and see the result in both rectangular and...

basic

8,406 4.7 1 min

Showing 253 to 264 of 545 results

tutorial Math

Percentages Without the Headache

Every "X% of Y" problem, every "what percent of", every percent-change question — written out the way you'd actually say them.

Daniel Oh

Jan 16, 2026 3 min

explainer Statistics

Standard Deviation in Five Minutes

Standard deviation is "average distance from the average". That one sentence covers 90% of everything you ever need to remember about it.

Daniel Oh

Dec 6, 2025 3 min

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Browse categories

Daniel Oh

Beam Second Moment of Area (I) Calculator

Piotroski F-Score Financial Strength Calculator

Allele Frequency Calculator

Bacterial Growth Calculator

Final Grade Calculator

Area of a Circle Calculator

Moody Chart Friction Factor from Reynolds Number and Roughness Calculator

Spearman Rank Correlation from Σd² Calculator

Two-Line 2-D Intersection Calculator

Vector Projection of a onto b Calculator

3-D Rodrigues Rotation Matrix Calculator

Complex Number Calculator

Percentages Without the Headache

Standard Deviation in Five Minutes