Daniel Oh
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
Other / Tech

Password Entropy Calculator

Compute the bits of entropy of a password from the size of the character set drawn from (lowercase, uppercase, digits, s...

basic
11,995 4.5 1 min
Math / Geometry

2D Rotation Matrix Calculator

Compute the entries of a 2-dimensional rotation matrix R(θ) = [[cos θ, −sin θ], [sin θ, cos θ]] and the result of rotati...

basic
3,748 4.6 1 min
Math / Geometry

Inverse Trigonometry Calculator

Compute the inverse-sine, inverse-cosine, and inverse-tangent of a value, returning the result in both radians and degre...

basic
15,064 5.0 1 min
Everyday Life / Time & Date

Age Calculator

Calculate your exact age in years, months, weeks, and days from a date of birth and a reference date.

Featured basic
21,515 4.8 1 min
Math / Percentage

Exponential Decay Calculator

Compute the remaining quantity after time t for an exponentially decaying process N(t) = N₀ · e⁻ᵏᵗ, plus the half-life.

basic
11,753 4.1 1 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 Daniel Oh
3 min

Reviewed by Daniel Oh

These calculators were technically reviewed by Daniel Oh for accuracy.