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
Everyday Life / Time & Date

Tree Age Calculator

Estimate a tree's age from its trunk circumference at chest height and a species-specific annual growth factor.

basic
15,253 4.3 1 min
Math / Geometry

Sector Area Calculator

Compute the area of a circular sector ("pie slice") from the radius and the central angle in degrees.

basic
1,866 4.2 1 min
Math / Percentage

Logarithm Calculator

Compute the logarithm of any positive number in any base — change-of-base formula included.

basic
3,775 4.5 1 min
Other / Time & Date

Days Until Date Calculator

Count the number of days, weeks, months, and years between today and any chosen date — past or future.

basic
7,275 3.9 1 min
Chemistry / Solutions

pH Calculator

Convert between hydrogen-ion concentration and pH, and find pOH for the complementary side of the scale.

basic
2,294 4.2 1 min
Math / Percentage

Percentage Change Calculator

Compute the percentage change from an original value to a new value — positive for an increase, negative for a decrease.

basic
23,602 4.3 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