Steel Weight Calculator
Weight of steel plates, bars, and tubes
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Steel Weight Calculator turns the numbers behind weight of steel plates, bars, and tubes into a result, step by step. Type Dimension 1 (mm), Dimension 2 (mm) and Dimension 3 (mm) into Steel Weight; each keystroke re-runs the math. Steel Weight puts the headline number first. Steel Weight replaces guesswork. Nothing is uploaded while Steel Weight works, and the figures stay put. Steel Weight handles steel weight calculator beam plate bar kg the same way as related figures — one of the Engineering tools on CalcProMaster. Steel Weight shows formula, assumptions and result together. Open Steel Weight and enter your numbers.
What the defaults weigh
A steel plate 1,000 mm × 500 mm × 10 mm weighs 39.25 kg.
Volume is 0.005 m³ and steel density is 7,850 kg/m³, so 0.005 × 7,850 = 39.25. The whole calculation is geometry plus one constant.
Volume first, then density
Weight = volume × 7,850 kg/m³ for carbon steel. Volume depends on the shape:
- Plate. L × W × T, all in metres.
- Round bar. π × (d/2)² × L.
- Square bar. side² × L.
- Tube. π × (R² − r²) × L, using outer and inner radius.
Worked example: 1000 × 500 × 10 mm plate
Convert to metres: 1.0 × 0.5 × 0.01 = 0.005 m³.
Weight = 0.005 × 7,850 = 39.25 kg.
When the shape is a round or square bar, the dimensions entered are the cross-section and the third field is length — a 20 mm round bar one metre long weighs π × 0.01² × 1 × 7,850 = 2.47 kg.
Density by alloy
7,850 kg/m³ is plain carbon steel. Stainless steels run 7,900–8,000; cast iron about 7,200; aluminium 2,700. Using the steel figure for aluminium overstates the weight almost threefold, which matters when the number is going into a lifting plan.
Why the calculated weight and the delivery note differ
- Nominal versus actual thickness. A “10 mm” plate is often 9.5 mm in practice, a 5% weight difference.
- Mill tolerance. Standards allow a percentage over and under nominal, and the mill is paid on the actual figure.
- Surface finish. Galvanising adds roughly 3–7% to the weight.
- Cutting. A plasma or laser kerf removes a small amount, and the offcut still exists if you are paying for the whole plate.
Where this figure is used
Freight quotes, crane and sling capacity, pallet ratings and structural dead loads all start from this number. Add a margin for lifting gear and fixings, and check the capacity figure rather than the intended weight.
Frequently Asked Questions
Why does a 1 m × 0.5 m × 10 mm plate weigh 39.25 kg?
Volume is 1.0 × 0.5 × 0.01 = 0.005 m³, and carbon steel weighs 7,850 kg/m³. 0.005 × 7,850 = 39.25 kg.
What density should I use for stainless steel?
About 7,900–8,000 kg/m³ depending on grade, roughly 1–2% heavier than carbon steel. Aluminium at 2,700 kg/m³ is the bigger difference — nearly a third of the steel figure.
How do I weigh a round bar?
π × (diameter/2)² × length × 7,850, with dimensions in metres. A 20 mm bar one metre long is π × 0.0001 × 7,850 = 2.47 kg.
Why is the delivered weight higher than calculated?
Mill tolerances allow plate to run over nominal thickness, galvanising adds 3–7%, and the supplier may bill on theoretical weight with a positive tolerance built in.
Does the tube option use outside or inside diameter?
The calculation uses an outer and an inner radius so the wall thickness is handled correctly. Entering the outer diameter twice gives the weight of a solid bar, not a tube.
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