About this calculator
Use this calculator for tanks, containers, concrete pours, packaging and solid parts. Volume tells you capacity (in litres or gallons) or, multiplied by density, the weight. Surface area is useful for painting, coating, insulation and heat-transfer estimates.
Formula
Box (cuboid)
V = LWH S = 2(LW + LH + WH)
Cylinder
V = πr²h S = 2πr(r + h)
r = diameter ÷ 2. Surface area includes both ends.
Sphere
V = 4⁄3 πr³ S = 4πr²
Cone
V = πr²h ÷ 3 S = πr(r + √(r² + h²))
Right circular cone; surface area includes the base.
Worked example
- Box 2 × 3 × 4 m: volume 24 m³ (24 000 L), surface area 52 m².
- Cylinder tank 1 m diameter, 2 m high: volume = π × 0.5² × 2 = 1.571 m³ = 1571 L.
- Sphere 2 m diameter: volume = 4⁄3 × π × 1³ = 4.189 m³.
- Cone 6 m diameter, 4 m high: volume = π × 9 × 4 ÷ 3 = 37.70 m³; slant height 5 m; surface area = π × 3 × 8 = 75.40 m².
Assumptions and limitations
- Internal dimensions give capacity; external dimensions give the space a part occupies. Use the right one for your purpose.
- Perfect geometric shapes. Real tanks may have dished ends, fittings or sloping bottoms.
References
- Solid geometry formulas for prisms, cylinders, spheres and cones.
