How thick is a #5 rebar?

The correct choice reflects the standard thickness for a #5 rebar, which is indeed 5/8 inch in diameter. This size designation is part of a system used in the United States where the number indicates the eighths of an inch that correspond to the diameter of the rebar. For instance, a #5 rebar is designated as being 5 times 1/8 inch, which equals 5/8 inch.

Understanding this sizing is crucial in construction and reinforced concrete work, as choosing the correct size rebar is essential for ensuring structural integrity and compliance with building codes. Knowing the thickness helps builders determine how much load the rebar can handle and how to plan the spacing and placement within concrete pours.