Volume only, with explicit units
Rectangle: length × width × depth. Cylinder: π × radius² × height. Horizontal dimensions are in meters; depth or column height is in centimeters. Output is cubic meters.
Example and limitations
A 5 × 4 m slab at 15 cm thick has 3 m³ before allowance. The tool does not determine strength, reinforcement, safe dimensions or mix proportions; engineering design is separate.