What is surface area?
The total area covering the outside of a 3D object.
Surface Area Calculator
Find the total outer surface area of common 3D solids.
Select a solid
Choose a shape and enter the needed dimensions.
About this calculator
How to use Surface Area Calculator, plus the formulas and logic behind the results.
Tool description
Surface area totals the area of all outer faces (or the curved surface for a sphere).
How to use
- Select the solid.
- Enter positive dimensions.
- Select Calculate.
- Read total surface area.
Formulas & reference
Cube: 6a²Sphere: 4πr²Cylinder: 2πr(h + r)Rectangular prism: 2(lw + lh + wh)
Surface tips
- Cube has 6 equal faces
- Sphere has no flat faces
- Open cylinder would omit bases
- Units are length²
Calculation logic
Applies the selected closed-surface formula. Cylinder includes two bases. Uses M_PI where needed.
Cylinder result is total surface (lateral + bases).
Surface Area Calculator FAQ
Common questions about this calculator and how to use the results.
How do you find cube surface area?
6 times side squared.
Does cylinder include the tops?
Yes—this tool reports total surface 2πr(h+r).
How do you find prism surface area?
Sum the areas of all six faces: 2(lw+lh+wh).
Is lateral area different?
Yes—lateral excludes bases.
Must dimensions be positive?
Yes.