Advertisement
Advertisement

Rebar Weight Calculator

Metric Rebar Weight Formula: Weight (kg/m) = d² ÷ 162

Example: A 12mm metric rebar weighs approximately 0.89 kg per meter (0.60 lbs/ft).

Estimate reinforcing steel bar weights for concrete reinforcement schedules. Supports imperial sizes (#3 to #11) and metric diameters.

Parameters

Calculated Weight

Total Weight 10.6 kg (23.4 lbs)
Unit Weight 0.89 kg/m

Standard Rebar Dimensions & Weights

Bar Designation Nominal Diameter (mm) Unit Weight (kg/m) Unit Weight (lbs/ft)
#3 (3/8") 9.53 mm 0.56 kg/m 0.376 lbs/ft
#4 (1/2") 12.7 mm 0.99 kg/m 0.668 lbs/ft
#5 (5/8") 15.88 mm 1.55 kg/m 1.043 lbs/ft
#6 (3/4") 19.05 mm 2.24 kg/m 1.502 lbs/ft
#8 (1") 25.4 mm 3.97 kg/m 2.67 lbs/ft
10mm (Metric) 10 mm 0.617 kg/m 0.415 lbs/ft
12mm (Metric) 12 mm 0.888 kg/m 0.597 lbs/ft
16mm (Metric) 16 mm 1.58 kg/m 1.061 lbs/ft
20mm (Metric) 20 mm 2.47 kg/m 1.661 lbs/ft
25mm (Metric) 25 mm 3.85 kg/m 2.591 lbs/ft

Rebar in Concrete Construction

Reinforcing steel bars (rebar) are embedded in concrete to provide tensile strength. Concrete is strong in compression but weak in tension — rebar compensates by carrying tensile loads. Together they form reinforced concrete (RC), the dominant structural material in modern construction.

In structural engineering, rebar schedules (bar bending schedules in the UK, rebar lists in the US) list all bar sizes, shapes, and quantities for a project. Accurately calculating rebar weight is essential for procurement, cost estimation, and shipping logistics.

Rebar Formula Derivation

The d²/162 formula comes from: Weight = Cross-section Area × Length × Density

Area = π × (d/2)² = πd²/4
= πd²/4 × 7850 kg/m³ ÷ 1,000,000 (mm² → m²)
= d² × 7850π ÷ 4,000,000
≈ d² ÷ 162.2 ≈ d² ÷ 162
Valid for mild steel density = 7850 kg/m³

Frequently Asked Questions — Rebar Weight

What is the formula for rebar weight per meter?
The weight of steel rebar in kg per meter: Weight = d² ÷ 162, where d is the nominal diameter in millimeters. This formula derives from: weight = cross-section area × density = (πd²/4) × 7850 kg/m³ ÷ 1,000,000 = d²/162. Example: 16mm rebar = 16²/162 = 1.58 kg/m.
How much does a #4 rebar weigh?
A standard #4 imperial rebar (1/2 inch diameter, 12.7mm) weighs 0.668 lbs per foot or 0.994 kg/m. A 20-foot stick of #4 rebar weighs approximately 13.4 lbs (6.07 kg).
How much does a #5 rebar weigh?
A #5 rebar (5/8 inch diameter, 15.88mm) weighs 1.043 lbs per foot or 1.55 kg/m. A standard 20-foot stick weighs approximately 20.9 lbs (9.47 kg).
What is the weight of 10mm rebar per meter?
10mm metric rebar weighs 10² ÷ 162 = 0.617 kg/m (0.415 lbs/ft). A 6-meter standard bar weighs approximately 3.70 kg.
How do I calculate total rebar weight for a project?
1. List all rebar sizes and their total linear lengths. 2. Calculate weight per meter for each size using d²/162. 3. Multiply unit weight by total length. 4. Sum all weights. Add 5–10% for lap splices and cutting waste.

Related Engineering & Construction Tools

Steel Weight Calculator Concrete Mix Ratio Concrete Volume Calculator Board Feet Calculator Roofing Square Calculator Weight Converter