Box: V = length x width x height. Cylinder: V = πr²h. Sphere: V = 4/3 πr³. Cone: V = 1/3 πr²h. Surface areas are 2(lw + lh + wh) for a box, 2πr(r + h) for a cylinder, 4πr² for a sphere and πr(r + √(r² + h²)) for a cone.
Example: a box 4 x 3 x 2 holds 24 cubic units; a cylinder with radius 3 and height 5 holds 141.37.
Any, as long as every dimension uses the same one. Volume comes out in cubic units (cm gives cm³).
1,000 cm³ is 1 litre. For other units use the volume converter.
A cone with the same base and height as a cylinder fills exactly one third of it.
See also: circle calculator · volume converter · concrete calculator