Rebar Weight Calculator & Size Chart
Rebar weight ranges from 0.376 lb/ft (#3) to 13.6 lb/ft (#18) under ASTM A615. A #4 bar (½″) weighs 0.668 lb/ft.
| Rebar Size | Nominal Diameter (in) | Unit Weight (lb/ft) | Nominal Mass (kg/m) |
|---|---|---|---|
| #3 | 0.375 | 0.376 | 0.560 |
| #4 | 0.500 | 0.668 | 0.994 |
| #5 | 0.625 | 1.043 | 1.552 |
| #6 | 0.750 | 1.502 | 2.235 |
| #7 | 0.875 | 2.044 | 3.042 |
| #8 | 1.000 | 2.670 | 3.973 |
| #9 | 1.128 | 3.400 | 5.060 |
| #10 | 1.270 | 4.303 | 6.403 |
| #11 | 1.410 | 5.313 | 7.906 |
| #14 | 1.693 | 7.650 | 11.38 |
| #18 | 2.257 | 13.600 | 20.24 |
Nominal data per ASTM A615 / A615M-22 Standard Specification and CRSI Reinforcing Steel Manual.
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Sources & Governing Codes
- Wikipedia Rebar Definition & Specifications: Wikipedia Rebar Definition & Specifications View Standard
- ASTM A615 Carbon-Steel Reinforcing Bars Standard: ASTM A615 Carbon-Steel Reinforcing Bars Standard View Standard
Frequently Asked Questions (FAQ)
What is the standard length of a rebar joint?
In the United States, standard stock rebar lengths are distributed in 20-foot, 40-foot, or 60-foot lengths. In metric regions (GCC and Europe), reinforcing steel bars are commonly inventory stocked in 6-meter or 12-meter lengths.
How is rebar weight calculated manually?
You can calculate rebar weight by multiplying the bar's nominal unit weight rate (e.g., 0.668 lb/ft for #4 rebar) by the single bar length and the total quantity: Weight = Unit Weight × Length × Quantity.
What is the difference between ASTM A615 and ASTM A706 rebar?
ASTM A615 is carbon steel rebar intended for general reinforcement structures. ASTM A706 specifies low-alloy reinforcing steel designed specifically for enhanced weldability and seismic structural safety.
Why does metric rebar use the 0.006165 constant?
The metric mass constant 0.006165 is derived from physical geometry. By multiplying the volume of a cylinder of diameter 'd' mm per 1 meter length (π × (d/2000)² × 1) by structural steel density (7,850 kg/m³), you obtain the nominal weight constant of 0.00616539.
What are the standard rebar grades?
Rebar grades designate the steel's yield strength. In the US system, Grade 40, 60, 75, 80, and 100 represent yield thresholds in ksi. In metric classifications, Grade 280, 420, 500, and 520 represent yield limits in Megapascals (MPa).
How do you convert US rebar sizes to metric diameters?
US sizes represent bar diameter in eighths of an inch. A #4 bar is 4/8" = 0.500" (12.7 mm). In metric layouts, this corresponds to a 12mm nominal diameter bar (or 13mm under SASO standards).
How much weight does rebar add to concrete slabs?
Rebar reinforcement adds approximately 1.5 to 2.5 pounds of steel per square foot of slab, depending on reinforcement grid spacing, accounting for roughly 1.5% of total structural volume.
What does the marking on a rebar represent?
Markings designate the manufacturing mill code, the nominal bar size, the steel type (e.g., 'S' for A615 carbon, 'W' for A706 low-alloy), and the yield grade mark (e.g., '60' or Grade 420 lines).
Does rusted rebar lose weight or structural capacity?
Light surface rust is acceptable and enhances concrete adhesion. Scaling, flaking, or pitting indicates deep oxidation that reduces the steel's cross-sectional area and weight capacity, which fails inspection.
How do you calculate rebar overlap/lap splice length?
Lap splice overlap length is typically 40 to 60 times the nominal bar diameter (40d to 60d). For a #4 rebar (0.5 inch diameter), the lap splice requires a 20-inch overlap joint.
What is the weight of #4 rebar per foot?
A #4 rebar (0.5-inch nominal diameter) weighs exactly 0.668 lbs per foot (0.994 kg per meter) under ASTM A615 standards.
How many feet of rebar are in a 1-ton bundle?
A standard 2,000 lb ton bundle contains approximately 2,994 feet of #4 rebar or 1,887 feet of #5 rebar.
What is rebar lap splice clearance code?
IRC and ACI 318 require lap splices to maintain at least 1 inch of concrete clear cover from surrounding forms or ground soil.
How do epoxy-coated rebar weights compare to black rebar?
Epoxy-coated rebar (ASTM A775) has identical nominal steel weight to black steel rebar; the protective polymer coating adds negligible weight (less than 0.1%).
What diameter is #6 rebar in inches and mm?
A #6 rebar has a nominal diameter of 6/8 inch (0.750 inches or 19.05 mm) and weighs 1.502 lbs per foot.
What rebar size is required for residential driveways?
Residential driveways typically specify #4 rebar spaced 12 inches to 18 inches on center in a grid pattern.
How is stirrup rebar weight calculated?
Stirrup weight equals the out-to-out perimeter length of the stirrup plus hook extensions multiplied by the unit weight of the tie bar size (typically #3 or #4).
What is the difference between Grade 60 and Grade 80 rebar?
Grade 60 rebar yields at 60,000 psi (420 MPa), whereas Grade 80 yields at 80,000 psi (550 MPa), allowing structural designs to use smaller bar diameters for heavy loads.
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