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

Math

Five-Number Summary from Up-to-9 Sorted Values Calculator

Compute the five-number summary (min, first quartile Q1, median, third quartile Q3, max), interquartile range (IQR), and...

basic

16,972 4.3 1 min

Physics / Mechanics

Specific Heat Calculator

Compute the heat required to change the temperature of a substance from its mass, specific heat capacity, and temperatur...

basic

19,563 4.8 1 min

Chemistry / Solutions

Boyle's Law Calculator

Find the missing pressure or volume in Boyle's law (P₁V₁ = P₂V₂) for an ideal gas at constant temperature.

basic

21,147 4.8 1 min

Statistics / Probability

Hypergeometric Distribution Mean Calculator

Calculates the mean (expected value) of a hypergeometric distribution from population size N, successes K, and sample si...

basic

9,203 4.8 1 min

Math / Percentage

Exponential Growth and Decay Rate Calculator

Computes y(t) = y₀ · e^(r·t) for continuous exponential growth (r > 0) or decay (r < 0). Also calculates the doubling ti...

basic

18,685 4.9 1 min

Statistics / Probability

Permutation & Combination Calculator

Count how many ways to choose or arrange r items from a set of n — both nPr and nCr, with a short breakdown of why they...

basic

17,614 4.0 1 min

Physics / Mechanics

Pressure Calculator

Compute pressure as force per unit area in pascals, with quick conversions to common engineering units.

basic

517 4.8 1 min

Physics / Mechanics

Column Euler Buckling Load Calculator

Calculates the Euler critical buckling load P_cr = π²EI/(KL)², where E is elastic modulus, I is second moment of area, K...

basic

24,444 4.4 1 min

Math

Sigmoid (Logistic) Function Calculator

Compute the standard logistic / sigmoid function σ(x) = 1 / (1 + e^(−x)) — the canonical S-shaped activation function an...

basic

15,719 4.3 1 min

Math / Geometry

Cylindrical to Cartesian Coordinates Calculator

Convert a 3-D point from cylindrical coordinates (r, θ, z) to Cartesian (x, y, z): x = r·cos θ, y = r·sin θ, z = z. Usef...

basic

3,292 4.4 1 min

Physics / Mechanics

Friction Force Calculator

Compute the friction force on a horizontal surface from the coefficient of friction and the object's weight.

basic

15,037 3.9 1 min

Health

Modified Early Warning Score (MEWS) Calculator

Calculates MEWS from systolic BP, heart rate, respiratory rate, temperature, and AVPU consciousness level. Score ≥ 5 ind...

basic

570 4.8 1 min

Showing 325 to 336 of 566 results

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

Mar 20, 2026 3 min

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 7, 2026 3 min

Reviewed by Daniel Oh

These calculators were technically reviewed by Daniel Oh for accuracy.

Health

Young's Rule Pediatric Dose Calculator

Calculate an age-based pediatric dose from a known adult dose using Young’s Rule. A quick educational tool for students...

basic

22,628 5.0 1 min

Best Free Calculator

Browse categories

Daniel Oh

Five-Number Summary from Up-to-9 Sorted Values Calculator

Specific Heat Calculator

Boyle's Law Calculator

Hypergeometric Distribution Mean Calculator

Exponential Growth and Decay Rate Calculator

Permutation & Combination Calculator

Pressure Calculator

Column Euler Buckling Load Calculator

Sigmoid (Logistic) Function Calculator

Cylindrical to Cartesian Coordinates Calculator

Friction Force Calculator

Modified Early Warning Score (MEWS) Calculator

Standard Deviation in Five Minutes

Percentages Without the Headache

Reviewed by Daniel Oh

Young's Rule Pediatric Dose Calculator