Metal Weight Calculator

Every result here is one multiplication chain: cross sectional area from the shape, times length, times density. What changes is the area expression. A flat bar is width times thickness, a round bar is pi times the radius squared, a round tube is the annulus given by pi times the outer radius squared minus the inner radius squared, and a square tube is the outer side squared minus the inner side squared, where the inner side is the outer side less twice the wall. Densities are quoted in pounds per cubic inch: mild steel 0.2836, which is 490 pounds per cubic foot or 7,850 kg per cubic meter; aluminum 6061 0.0975, about 2,700 kg per cubic meter; copper 0.323; and Ti-6Al-4V about 0.160. Those ratios drive material selection as much as price does. Aluminum is roughly one third the weight of steel by volume, but its elastic modulus is also about one third, near 10 million psi against 29 million for steel, so an aluminum section matched to a steel one for stiffness must be substantially thicker and the weight saving is smaller than the density ratio suggests. Alloying moves density very little: 7075 at 0.1013 differs from 6061 by only a few percent despite far higher strength. This is a theoretical weight from nominal dimensions. Mill tolerances on thickness, width and straightness under specifications such as ASTM A6 mean delivered pieces commonly differ by a few percent, and coatings such as hot dip galvanizing add material, so lift planning and freight quotes should carry a margin.

Weight tables for structural shapes were commercial documents long before they were engineering standards. Carnegie Steel published its Pocket Companion in 1873 listing section dimensions and theoretical weights for rolled shapes, and competing mills issued rival handbooks that were not interchangeable. The American Institute of Steel Construction was founded in 1921 and published the first edition of its Steel Construction Manual in 1927, consolidating section properties and theoretical weights into one reference, while ASTM A36 later became the workhorse carbon structural steel grade. The convention of tabulating a theoretical weight from nominal dimensions and a fixed density, rather than a measured weight, dates from those handbooks and is still how mills quote. The lighter metals in the list are much newer. Aluminum was a precious curiosity until Charles Martin Hall and Paul Heroult independently developed electrolytic smelting in 1886, which collapsed its price within a decade. Alcoa introduced the magnesium silicon alloy now designated 6061 in 1935, and the zinc bearing 7075 was developed in Japan by Sumitomo in the 1930s and adopted for aircraft structure. Titanium alloy Ti-6Al-4V was developed in the United States in the early 1950s and remains the dominant titanium alloy by volume. ASM International, founded in 1913 as the American Society for Steel Treating, has published the handbook series that standardized the density and property data these calculations depend on.