Surface Area Calculator

Choose a 3D shape and enter its dimensions to calculate the surface area.

How to Use the Surface Area Calculator

Choose a 3D shape first, since surface area needs a different set of dimensions for a sphere than for a cone or a rectangular prism.

Cube:      6 × side²
Box:       2(lw + lh + wh)
Sphere:    4 × π × radius²
Cylinder:  2πr(r + h)
Cone:      πr(r + slant),  slant = √(r² + h²)

A cube's six identical square faces make its formula the simplest here — one face's area, side², times six. A box generalizes that to three different pairs of matching faces (top/bottom, front/back, left/right), which is why its formula sums three separate products instead of one multiplication. This Surface Area Calculator covers all five common solids.

The cone is the odd one out, needing slant height rather than vertical height — its curved side isn't flat like a cylinder's, so the distance along the surface from tip to base edge matters more than straight-up distance. That slant height itself comes from the Pythagorean theorem, applied to radius and height.