Steel Weight Calculator
Round, square, flat, plate, pipe, angle, and AISC W-sections → weight in pounds and kilograms.
1 × 20 ft @ 26.00 lb/ft
Method+
For prismatic sections: W = A · L · ρ, where ρ = 0.2836 lb/in³ (490 lb/ft³).
AISC wide-flange weights are taken from the section designation (e.g., W14x68 = 68 lb/ft).
Pipe: A = π(r_o² − r_i²). Plate: A = W · t.
Mill tolerance is ±2% per ASTM A6. Add 4-8% for connections, copes, base plates, and stubs when bidding.
Frequently asked questions
What is the density of steel?+
490 lb/ft³ (0.2836 lb/in³) for carbon and low-alloy structural steel. Stainless is about 1% denser; aluminum is ~1/3 of steel.
How accurate are the AISC weights?+
The 'W14x68' designation literally means 68 lb/ft — they're nominal mill weights. Actual pieces vary ±2% per ASTM A6 tolerances.
Plate weight rule of thumb?+
Steel plate ≈ 40.8 lb/ft² per inch of thickness. A ½″ × 4′ × 8′ plate weighs ~653 lb.
Pipe vs. round bar — what's the difference?+
Round bar is solid (full circular area). Pipe is hollow — subtract the inner-area volume from the outer-area volume before multiplying by density.
Why does the contractor's takeoff differ from mine?+
Connections, splices, copes, base plates, and stub members add 4-8% beyond beam-line weight. Add that as 'connection allowance' to your raw takeoff.
Can I get a price?+
Multiply weight × $/lb. Plate and HSS run $1.20-1.80/lb; wide-flange $1.10-1.50/lb in 2025 USD. Add shop fab ($0.30-0.70/lb) and erection separately.