How many standard deformed bar sizes are there?

• A. 11 Bar sizes
• B. 9 Bar sizes
• C. 12 Bar sizes
• D. 14 Bar sizes

Answer: (A)

Standard deformed bar sizes refer to the common diameters in which reinforcing bars are manufactured and kept in stock. In typical U.S. practice, there are 11 standard sizes: #3, #4, #5, #6, #7, #8, #9, #10, #11, #14, and #18. This range covers small-diameter bars for light reinforcement up to the larger bars used for heavier members, giving designers a practical set to work with while fabricators can stock these sizes. The size is the nominal diameter and directly relates to the reinforcing area available to resist forces.

That’s why this option is correct: it reflects the standard stock sizes used in common practice. Fewer sizes would miss some of the larger bars needed for bigger members, while more sizes would include diameters not typically treated as standard stock.