Surface Area Calculator
Calculate the surface area of a cube, sphere, cylinder, cone and more. Free surface area calculator showing the formula used for each solid.
About the Surface Area Calculator
This free surface area calculator finds the total surface area of common 3D solids — cube, rectangular box, sphere, cylinder, cone and more. Pick the shape, enter its dimensions, and get the surface area instantly along with the exact formula used, so you can follow the working.
Surface area is the total area of all the outer faces or curved surfaces of a solid. Each shape has its own formula: a cube is 6s², a sphere is 4πr², a cylinder is 2πr(r + h) and a cone is πr(r + l). The calculator uses the precise value of π and shows results in square units matching your input.
Students in geometry, and anyone estimating paint, wrapping, plating or material for a curved or boxy object, use this daily. The calculator is unit-agnostic — enter centimetres and the area is in square centimetres. Everything runs in your browser.
How to Use the Surface Area Calculator
- 1Choose the solid: cube, box, sphere, cylinder or cone.
- 2Enter the required dimensions (side, radius, height and so on).
- 3Read the total surface area instantly.
- 4Check the formula panel to see how the area was derived.
Frequently Asked Questions
How do I calculate the surface area of a sphere?
Use 4πr². A sphere of radius 5 has a surface area of 4 × π × 25 = 314.16 square units. Note that the surface area of a sphere is exactly four times the area of its circular cross-section (πr²).
What is the surface area of a cylinder?
Total surface area is 2πr(r + h) — the two circular ends (2πr²) plus the curved side (2πrh). A cylinder with radius 3 and height 10 has area 2π × 3 × (3 + 10) = 245.04 square units. Omit the ends for lateral (side-only) area.
How do I find the surface area of a cone?
Use πr(r + l), where l is the slant height, not the vertical height. If you know the vertical height h, the slant height is l = √(r² + h²). A cone with radius 3 and slant height 5 has area π × 3 × (3 + 5) = 75.40 square units.
What is the difference between surface area and volume?
Surface area measures the outside covering of a solid in square units; volume measures the space it holds in cubic units. Surface area matters for paint and material; volume matters for capacity. They use different formulas for the same shape.
How do I calculate the surface area of a box?
For a rectangular box with length l, width w and height h, the surface area is 2(lw + lh + wh). A box measuring 4 by 3 by 2 has area 2(12 + 8 + 6) = 52 square units — useful for gift wrapping or sheet material.