BYTETOOLS

Surface Area Calculator

Find total and lateral surface area for cubes, boxes, spheres, cylinders, cones, pyramids, capsules and prisms, with the exact formula shown for every shape.

87.964594
Total surface area (m²)
62.831853
Lateral surface area (m²)

Formula used

SA = 2πr(r + h), lateral = 2πrh

SA = 87.964594 m² · lateral = 62.831853 m²

What is the Surface Area Calculator?

The ByteTools Surface Area Calculator returns the total surface area — and, where it applies, the lateral (side-only) surface area — of eight solids: cube, rectangular box, sphere, cylinder, cone, square pyramid, capsule and triangular prism.

  • Total and lateral surface area side by side
  • Eight solids including capsule and triangular prism
  • Slant height computed and shown for cones and pyramids
  • Heron's formula for the triangular prism base
  • Formula printed under every result
  • 100% private — computed in your browser

How to use the Surface Area Calculator

  1. 1

    Choose a shape from the dropdown.

  2. 2

    Pick the measurement unit for your dimensions.

  3. 3

    Enter the dimensions — for example radius and height for a cylinder.

  4. 4

    Read the total and lateral surface area, plus the formula used.

  5. 5

    Click Copy to grab the total.

About the Surface Area Calculator

The ByteTools Surface Area Calculator returns the total surface area — and, where it applies, the lateral (side-only) surface area — of eight solids: cube, rectangular box, sphere, cylinder, cone, square pyramid, capsule and triangular prism. Cones and pyramids include the slant height in the working, and the triangular prism uses Heron's formula on its three sides.

It is built for geometry students checking homework, and for practical jobs like estimating paint, wrapping or sheet material, where the lateral area (walls only, no top or bottom) is often the number you actually need. The exact formula used is printed under every result.

All calculations run locally in your browser — nothing is uploaded, so it is instant, private and works offline. Metric and imperial units are both supported.

Frequently asked questions

What is the difference between total and lateral surface area?

Total surface area covers every face of the solid, including bases. Lateral surface area covers only the sides — for a cylinder that is the curved wall without the two circular ends. Use lateral area when painting walls or wrapping a label around a can.

How do you find the surface area of a cone?

First find the slant height l = √(r² + h²), then apply SA = πr(r + l). A cone with radius 3 and height 4 has slant height 5, so its total surface area is π × 3 × 8 ≈ 75.4 square units. The tool shows the slant height it computed.

Why does a sphere have no lateral surface area?

Lateral area only makes sense for solids with identifiable bases, like cylinders, prisms and cones. A sphere is one continuous curved surface with no base, so its only measure is the total surface area, 4πr². The calculator shows a dash for shapes where lateral area does not apply.

How is the surface area of a triangular prism calculated?

It is twice the triangle's area plus the perimeter of the triangle times the prism's length: SA = 2A + (a + b + c) × l. The tool computes the triangle's area from its three sides with Heron's formula, so you never need the triangle's height.

Can I use this to estimate paint or material?

Yes — surface area is exactly what paint coverage is quoted against. Compute the area, then divide by your paint's coverage per litre or gallon. Remember to use lateral area if you are not coating the top and bottom faces, and add a little extra for waste.

Related tools