Total surface area for common 3D shapes — cube, box, sphere, cylinder or cone.
The cone's surface area formula needs the slant length (l), but it's easier for you to measure the perpendicular height instead. The calculator asks for height and internally derives the slant length as √(r² + h²), so entering the slant length directly would give a wrong result.
It's the combined area of the two circular ends (2πr²) plus the curved side wall unrolled into a rectangle (2πrh) — the formula 2πr² + 2πrh adds both parts together for the total.
It's this shape's surface area divided by its volume for the dimensions you entered. A lower ratio means less surface area relative to volume — relevant for things like minimizing material use or heat loss for a given capacity.