US Rebar Sizes, Areas and Weights
Standard US reinforcing bars are named by number, and the number is the nominal diameter in eighths of an inch (a #4 bar is 4/8 = 1/2 inch). This table lists the nominal diameter, cross-sectional area and weight per foot for the inch-pound bar sizes made under ASTM A615 and A706. Contractors use it to estimate tonnage, and engineers use the area to check how much steel is in a footing, slab or wall.
| Bar size | Nominal diameterin | Nominal areain2 | Weightlb/ft | Soft metric size |
|---|---|---|---|---|
| #3 | 0.375 | 0.11 | 0.376 | #10 |
| #4 | 0.5 | 0.2 | 0.668 | #13 |
| #5 | 0.625 | 0.31 | 1.043 | #16 |
| #6 | 0.75 | 0.44 | 1.502 | #19 |
| #7 | 0.875 | 0.6 | 2.044 | #22 |
| #8 | 1.0 | 0.79 | 2.67 | #25 |
| #9 | 1.128 | 1.0 | 3.4 | #29 |
| #10 | 1.27 | 1.27 | 4.303 | #32 |
| #11 | 1.41 | 1.56 | 5.313 | #36 |
| #14 | 1.693 | 2.25 | 7.65 | #43 |
| #18 | 2.257 | 4.0 | 13.6 | #57 |
Notes
- Sizes #12, #13, #15, #16 and #17 are not standard. After #11 the series jumps to #14 and #18.
- Deformed bars have ribs, so the nominal diameter is the diameter of a plain round bar with the same weight per foot.
- Grade (for example Grade 60, meaning 60,000 psi minimum yield strength) is a separate property from size and is rolled onto the bar as a mark or a number.
- To estimate total weight, multiply the bar length in feet by the weight per foot, then add an allowance for laps, hooks and waste.
Frequently asked questions
How big is #4 rebar?
A #4 bar has a nominal diameter of 0.500 inch (1/2 inch), a cross-sectional area of 0.20 square inches, and weighs 0.668 pounds per foot.
Why do rebar numbers skip from #11 to #14?
The standard series stops at #11 and then offers only #14 and #18 as large sizes for heavy columns and foundations. Sizes #12, #13 and #15 to #17 are not produced as standard bars.
What does the soft metric bar size mean?
Mills mark bars in metric numbers (for example a #4 bar is marked 13, for about 13 mm). The bar is physically the same; only the label differs.
Sources
- ASTM A615/A615M, Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement, Table 1
- ASTM A706/A706M, Low-Alloy Steel Deformed and Plain Bars for Concrete Reinforcement
- Concrete Reinforcing Steel Institute (CRSI), https://www.crsi.org/
More reference tables
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