Rebar Weight & Tonnage Calculator
The SZW0 Rebar Weight Calculator delivers high-precision linear weight, total tonnage, and procurement estimates for reinforcing steel deformed bars. Fully calibrated to ASTM A615 (billet-steel) and ASTM A706 (low-alloy weldable steel) standards, this tool incorporates ACI 318 lap splicing and bending waste allowances for civil structural engineering.
- • #3 (3/8" / 9.5mm): 0.376 lbs/ft (0.560 kg/m)
- • #4 (1/2" / 12.7mm): 0.668 lbs/ft (0.994 kg/m)
- • #5 (5/8" / 15.9mm): 1.043 lbs/ft (1.552 kg/m)
- • #6 (3/4" / 19.1mm): 1.502 lbs/ft (2.235 kg/m)
Select Specification & Structural Inputs
Step-by-Step Rebar Tonnage Calculation Protocol
- Identify ASTM Bar Size Number: Imperial rebar numbers represent nominal diameters in eighths of an inch (e.g., #4 = 4/8" = 0.500" diameter).
- Calculate Aggregate Linear Footage: Multiply the unit stick length by the total count of required reinforcing bars.
- Apply ASTM Linear Unit Density: Multiply total linear footage by the specific bar weight factor (e.g., 0.668 lbs/ft for #4 rebar).
- Factor in ACI 318 Lap Splices & Hook Allowances: Add 5% to 10% structural margin for tension lap overlaps, stirrup end hooks, and trim waste.
Mathematical Formulas & ASTM Steel Density Specifications
Theoretical weight calculations for carbon steel rebar rely on the standard structural steel density of 0.2833 lb/in³ (7,850 kg/m³). Nominal weights are determined via the fundamental cross-sectional area formula:
ASTM A615 / A706 Standard Rebar Weight Reference Table
| Bar Size | Nominal Dia. (in) | Nominal Dia. (mm) | Unit Weight (lb/ft) | Unit Weight (kg/m) |
|---|---|---|---|---|
| #3 | 0.375" | 9.525 mm | 0.376 lb/ft | 0.560 kg/m |
| #4 | 0.500" | 12.700 mm | 0.668 lb/ft | 0.994 kg/m |
| #5 | 0.625" | 15.875 mm | 1.043 lb/ft | 1.552 kg/m |
| #6 | 0.750" | 19.050 mm | 1.502 lb/ft | 2.235 kg/m |
| #7 | 0.875" | 22.225 mm | 2.044 lb/ft | 3.042 kg/m |
| #8 | 1.000" | 25.400 mm | 2.670 lb/ft | 3.973 kg/m |
⚠️ Structural Detailing & Jobsite Material Loss Factors
- Tension Lap Splice Overlaps (ACI 318): Standard structural drawings require 40d to 60d lap splices at steel joints. Failing to include lap allowances causes shortfalls of up to 8% in total weight.
- 90° and 180° Hook Extensions: Standard seismic and structural stirrup hooks add extra linear bar length beyond nominal clear span dimensions.
- Mill Rolling Tolerance Variations: ASTM A615 permits a weight tolerance of ±6% per individual bar bundle during mill fabrication.
Frequently Asked Questions
What is the difference between Grade 60 and Grade 80 rebar?
Grade 60 steel has a minimum yield strength of 60,000 psi (414 MPa), whereas Grade 80 offers 80,000 psi (552 MPa). Both grades share identical volumetric weights and densities.
How many feet of #4 rebar are in a 1-ton bundle?
Since #4 rebar weighs 0.668 lbs per foot, a standard 2,000 lb US short ton bundle contains approximately 2,994 linear feet (~150 sticks of 20-ft length).