What is the diameter of re-bar used in column?

The diameter of rebar used in columns typically ranges from 12 mm to 32 mm (approximately 0.5 to 1.25 inches), depending on the structural requirements and design specifications. Commonly, for residential and commercial buildings, 16 mm to 20 mm (0.63 to 0.79 inches) rebar is often used. The specific diameter is determined by factors such as load-bearing capacity, column height, and building codes. Always consult structural engineers or design codes for precise requirements.