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

Chemistry / Solutions

Freezing Point Depression Calculator

Compute the freezing-point depression of a solution from molality, the solvent's cryoscopic constant, and the van't Hoff...

basic

24,267 4.8 1 min

Health

GFR (MDRD 4-Variable) Calculator

Estimates GFR using the 4-variable MDRD formula: eGFR = 175 × (Scr)^−1.154 × (Age)^−0.203 × 0.742 (if female) × 1.212 (i...

basic

488 4.7 1 min

Statistics

Relative Risk (Risk Ratio) Calculator

Compute relative risk (risk ratio) from a 2×2 contingency table. RR is the ratio of the probability of an outcome in the...

basic

11,436 4.4 1 min

Statistics / Probability

Normal Distribution PDF Calculator

Compute the probability density function of a normal distribution N(μ, σ²) at a given value x, using f(x) = exp(−(x − μ)...

basic

19,290 4.9 1 min

Math / Geometry

Cross Product Calculator

Compute the cross product (vector product) of two 3-dimensional vectors, plus its magnitude — useful for torque, angular...

basic

1,412 4.8 1 min

Physics

Decibel to Linear Power Ratio Converter

Converts between decibels and linear power ratio: P₂/P₁ = 10^(dB/10); dB = 10·log₁₀(P₂/P₁). Also handles voltage ratios:...

basic

9,560 4.5 1 min

Math / Percentage

Trapezoidal Rule (Single Interval) Calculator

Approximate the definite integral ∫ from a to b of f(x) dx with a single trapezoid: (b − a)/2 × (f(a) + f(b)).

basic

5,799 4.0 1 min

Physics / Mechanics

Escape Velocity Calculator

Compute the escape velocity from a celestial body's surface from its mass and radius.

basic

14,483 4.2 1 min

Math

Shannon Entropy of a 3-Outcome Discrete Distribution Calculator

Compute the Shannon entropy H of a 3-outcome discrete distribution: H = −Σ pᵢ · log₂ pᵢ, in bits. Entropy is the average...

basic

9,909 4.6 1 min

Physics / Mechanics

Spring Period (Mass on a Spring) Calculator

Compute the natural period and frequency of an ideal mass-spring oscillator from the mass m and the spring constant k.

basic

16,152 4.1 1 min

Physics / Mechanics

Impulse and Change in Momentum from Force and Time Calculator

Calculates impulse J = F · Δt and the resulting change in momentum. Given the object mass, also computes the change in v...

basic

19,187 4.3 1 min

Math

Linear Regression Slope from Sums Calculator

Compute the OLS slope coefficient of a simple linear regression y = a + b·x directly from the five paired-sample summary...

basic

6,586 4.0 1 min

Showing 265 to 276 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

Freezing Point Depression Calculator

GFR (MDRD 4-Variable) Calculator

Relative Risk (Risk Ratio) Calculator

Normal Distribution PDF Calculator

Cross Product Calculator

Decibel to Linear Power Ratio Converter

Trapezoidal Rule (Single Interval) Calculator

Escape Velocity Calculator

Shannon Entropy of a 3-Outcome Discrete Distribution Calculator

Spring Period (Mass on a Spring) Calculator

Impulse and Change in Momentum from Force and Time Calculator

Linear Regression Slope from Sums Calculator

Percentages Without the Headache

Standard Deviation in Five Minutes