Surface Area Calculator
Find the surface area of common 3D shapes for painting, coating or wrapping.
What the Surface Area Calculator does
Surface area is the total area of every face, which is what you actually need when buying paint, cladding, insulation or wrapping material. Volume tells you what fits inside; surface area tells you what covers the outside.
Formula
Box = 2(lw + lh + wh)Cube = 6s²Cylinder = 2πr(r + h)Sphere = 4πr²Cone = πr(r + √(r² + h²))
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Shape | one of 5 options | Yes | — |
| Length | number | In some modes | Accepts more than 0. Shown Shape is Rectangular box. |
| Width | number | In some modes | Accepts more than 0. Shown Shape is Rectangular box. |
| Edge length | number | In some modes | Accepts more than 0. Shown Shape is Cube. |
| Radius | number | In some modes | Accepts more than 0. Shown in 3 of the 5 modes. |
| Height | number | In some modes | Accepts more than 0. Shown in 3 of the 5 modes. |
How to use it
- Choose Shape.
- Fill in the remaining inputs the form shows for your choice.
- Select Calculate.
Worked example
Painting a cylindrical silo 3 m across and 8 m tall, sides only.
- Shape
- Cylinder
- Radius
- 1.5
- Height
- 8
Curved surface = 2π × 1.5 × 8 ≈ 75.4 m².
Frequently asked questions
Should I include the base when painting?
Usually not for tanks and silos sitting on the ground. Use the lateral or curved surface figure instead of the total.