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

Electric Motor Efficiency from Input and Output Power Calculator

Calculates motor efficiency η = P_output / P_input, losses = P_in − P_out, and input current at a given voltage. Typical...

basic

13,009 4.6 1 min

Math

Sum of Cubes from 1 to n Calculator

Compute the closed-form sum of the first n positive cubes: 1³ + 2³ + ⋯ + n³ = (n·(n+1)/2)² = (Σk)². Note that the sum of...

basic

477 4.9 1 min

Statistics / Descriptive

Weighted Mean from Values and Frequencies Calculator

Calculates x̄_w = Σ(w_i · x_i) / Σw_i for up to six value/weight pairs. Used in grade calculations, portfolio returns, a...

basic

6,501 5.0 1 min

Physics

Open and Closed Pipe Resonance Harmonics Calculator

Calculates the first three resonant harmonic frequencies for both open (both ends open) and closed-one-end organ pipes....

basic

6,291 4.1 1 min

Physics

Fourier Series Fundamental Frequency and Period Calculator

Calculates fundamental frequency f₀ = 1/T, angular frequency ω₀ = 2πf₀, and the first 5 harmonics for a periodic signal....

basic

12,542 4.8 1 min

Health

Wells Criteria DVT Probability Score Calculator

Calculates the Wells DVT score to stratify risk: active cancer (+1), paralysis/plaster (+1), bed rest >3d (+1), along lo...

basic

5,009 4.8 1 min

Food / Drinks

Coffee Ratio Calculator

Compute how many grams of coffee to use for a chosen water volume and brew ratio (e.g., 1:16 for filter, 1:2 for espress...

basic

12,236 4.8 1 min

Physics / Electricity

Electric Power Calculator

Compute electric power from any two of voltage, current, or resistance using P = VI, P = I²R, and P = V²/R.

basic

25,027 4.3 1 min

Health

Thermic Effect of Food TEF from Macros Calculator

Calculates the Thermic Effect of Food (TEF) — energy expended during digestion and absorption — from macronutrient calor...

basic

5,352 4.1 1 min

Statistics / Probability

Exponential Distribution PDF Calculator

Compute the probability density function f(t) = λ · e^(−λt) and the survival function S(t) = e^(−λt) of an exponential d...

basic

19,614 4.8 1 min

Physics

Coefficient of Performance — Heat Pump and Refrigerator Calculator

Calculates the Carnot COP for a heat pump COP_HP = T_H/(T_H−T_C) and for a refrigerator COP_R = T_C/(T_H−T_C). Also show...

basic

22,319 4.7 1 min

Math / Percentage

Attendance Percentage Calculator

Compute the attendance percentage from classes attended and total classes, plus the maximum number of additional absence...

basic

11,644 4.9 1 min

Showing 37 to 48 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

Calcify

Browse categories

Daniel Oh

Electric Motor Efficiency from Input and Output Power Calculator

Sum of Cubes from 1 to n Calculator

Weighted Mean from Values and Frequencies Calculator

Open and Closed Pipe Resonance Harmonics Calculator

Fourier Series Fundamental Frequency and Period Calculator

Wells Criteria DVT Probability Score Calculator

Coffee Ratio Calculator

Electric Power Calculator

Thermic Effect of Food TEF from Macros Calculator

Exponential Distribution PDF Calculator

Coefficient of Performance — Heat Pump and Refrigerator Calculator

Attendance Percentage Calculator

Percentages Without the Headache

Standard Deviation in Five Minutes