Metal Weight Calculator — Plate, Bar, Tube and Section Weight
Calculate the weight of any metal section — plate, round bar, square bar, hexagonal bar, round tube, or square hollow section — in kilograms and pounds. Select the metal alloy and enter dimensions in millimetres.
Metal type
Shape
mm
mm
mm
86.531 lb
39.25 kg
Carbon Steel- 1
Volume — L × W × T (mm³)
1,000 × 500 × 10 = 5,000,000 - 2
Volume (m³)
5,000,000 ÷ 10⁹ = 0.005 - 3
Weight (kg)
0.005 m³ × 7,850 kg/m³ = 39.250Volume in m³ multiplied by the alloy density gives mass in kg.
How does this calculator work?
Weight = Volume × Density. Volume from shape formula; all dimensions in mm. Key densities (kg/m³): carbon steel 7850, stainless 304 at 8000, aluminium 2700, copper 8900, brass 8500, titanium 4500, lead 11340. Divide mm³ by 10⁹ to get m³, then multiply by density for kg.
Formula
How this is calculated
Metal weight is volume multiplied by density. The volume formula depends on the shape: a plate is length × width × thickness; a round bar is (π/4) × diameter² × length; a square bar is side² × length; a hexagonal bar is (√3/2) × across-flats² × length (the exact area formula for a regular hexagon expressed from the across-flats distance); a round tube is (π/4) × (OD² − inner-D²) × length, where inner-D = OD − 2 × wall-thickness; a square hollow section uses (OD² − inner-side²) × length similarly.
All dimensions are entered in millimetres. The volume in mm³ is divided by 10⁹ to convert to cubic metres, then multiplied by the alloy density in kg/m³. Density values are standard reference values at room temperature: carbon steel 7850, stainless steel 304 at 8000, aluminium 2700, copper 8900, brass 8500, bronze 8800, titanium 4500, cast iron 7150, lead 11340, zinc 7130, nickel 8900 kg/m³.
These are nominal densities for common alloys. Real parts can vary ±1–3% depending on composition, heat treatment, and impurities. The calculator assumes a uniform cross-section throughout the length — tapered, bent, or composite sections should be broken into segments.
Frequently asked questions
Across-flats is the distance between two opposite parallel faces — the wrench size. It differs from the corner-to-corner diameter. The hexagon area from AF is (√3/2) × AF², which this calculator uses.
Multiply inches by 25.4 to get millimetres. The result in kg can then be multiplied by 2.20462 to get pounds, which the calculator also shows automatically.
Lead has a density of 11340 kg/m³ — about 4.2 times that of aluminium (2700 kg/m³) — because lead atoms are much heavier and pack together more closely. A 100 mm cube of lead weighs 11.3 kg versus 2.7 kg for aluminium.
Also known as
TG we-Calculate Editorial Team. (2026). Metal Weight Calculator — Plate, Bar, Tube and Section Weight [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/metal-weight-calculator
TG we-Calculate Editorial Team. "Metal Weight Calculator — Plate, Bar, Tube and Section Weight." TG we-Calculate. 2026. https://we-calculate.com/calculator/metal-weight-calculator.
TG we-Calculate Editorial Team, "Metal Weight Calculator — Plate, Bar, Tube and Section Weight," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/metal-weight-calculator
@misc{wecalculate_metal_weight_calculator, title = {Metal Weight Calculator — Plate, Bar, Tube and Section Weight}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/metal-weight-calculator}}, year = {2026}, note = {TG we-Calculate} }
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