Metal Weight Calculator
Find the weight of a metal bar, tube, sheet, or plate from its shape, size, and material — for steel, stainless, aluminum, copper, or brass.
Reviewed by the ToolNestr Editorial Team — July 2026
How the metal weight calculator works
Every solid piece of metal weighs its volume times its density. The calculator finds the cross-section area from the shape you pick, multiplies by the length to get the volume in cubic inches, and multiplies by the metal's density in pounds per cubic inch. Because the density is what changes between metals, the same bar in aluminum weighs about a third of what it does in steel.
Each shape has its own area formula. A round bar is pi divided by four times the diameter squared; a square bar is the side squared; a flat bar is width times thickness; a hexagon is about 0.866 times the width across the flats squared; and a round tube is the outside circle area minus the inside hole. Sheet and plate use width times thickness, with the length being the third dimension.
The densities come from standard ASTM material values: carbon steel 0.2836, stainless 0.289, aluminum 0.0975, copper 0.323, and brass 0.307 pounds per cubic inch. These are nominal figures used across the industry for estimating; the exact shipping weight of a specific heat of metal comes from the mill certificate.
Density values follow ASTM A29 and ASTM B209 reference tables for standard mill materials.
Pick shape and metal
Choose the profile and the alloy; the density is applied automatically.
Enter dimensions
Give the size in inches; the labels change to match the shape you chose.
Read the weight
See total weight, weight per foot, and the cross-section area.
The formula explained
Round bar area
A = π⁄4 × D². A 1-inch bar: π⁄4 × 1² = 0.785 in².
Volume and weight
W = A × L × ρ. A 36-inch steel bar: 0.785 × 36 × 0.2836 = 8.02 lb.
Same bar in aluminum
0.785 × 36 × 0.0975 = 2.76 lb — about 34% of the steel weight.
Worked example
A stainless flat bar 2″ wide, 0.25″ thick, 48″ long.
Why metal weight matters
Ordering and freight
Metal is priced and shipped by weight. Knowing the weight up front lets you compare quotes, check delivery tickets, and avoid overloading a trailer or hoist.
Structural loads
The self-weight of steel members feeds directly into beam, hanger, and foundation design, so an accurate per-foot figure is a first step in any load takeoff.
Fabrication and lifting
Shops size cranes, jigs, and welds around part weight. Choosing aluminum over steel can cut a lifted assembly to a third of the weight for the same shape.
Scrap value
Scrap yards pay by weight and metal type. Estimating the weight of offcuts and old material tells you what a load of scrap is worth before you haul it in.
Real-world context
Railing and fence fabricators lean on this calculator constantly for stock ordering. A 20-foot length of 1-inch round steel bar — a common size for handrail pickets — comes out to 0.7854 × 240 × 0.2836 = about 53.5 lb. Knowing that before the order goes in means the shop can plan how many bars fit on a pallet and whether a single worker can safely lift and carry one length.
Material selection often comes down to a direct weight comparison. A full 4×8 sheet of 1/8-inch steel plate weighs 576 × 0.2836 = 163.4 lb, while the same sheet in aluminum is 576 × 0.0975 = 56.2 lb — under a third of the weight. That difference is why aluminum shows up on ladders, trailer panels, and anything that gets lifted by hand, even though it costs more per pound than steel.
Scrap hauling is the other end of the use case. A 10-foot offcut of 1.5-inch OD steel tube with a 0.065-inch wall works out to a cross-section of 0.293 in², giving 0.293 × 120 × 0.2836 = about 10 lb — enough for a shop to estimate a scrap load's value at the yard's per-pound rate before hauling it in.
Common misconceptions
"Stainless steel and carbon steel weigh about the same, since they're both 'steel.'" Close, but not exact. Stainless (0.289 lb/in³) is roughly 2% denser than carbon steel (0.2836 lb/in³) because of its nickel and chromium content — a small difference on a single part, but it adds up on a large order.
"A tube's weight is basically the same as a solid bar of the same outside diameter." Not even close. A 1.5-inch OD tube with a thin wall removes most of the interior material — the tube example above weighs about 10 lb over 10 feet, while a solid 1.5-inch round bar the same length weighs roughly 60 lb. The hollow center is most of the volume.
Related calculators
Frequently asked questions
How do I calculate the weight of a metal bar?
Find the cross-section area, multiply by the length to get the volume, then multiply by the metal density. For a round steel bar, weight in pounds equals pi/4 times the diameter squared, times the length, times 0.2836 pounds per cubic inch, with all dimensions in inches.
What is the density of steel versus aluminum?
Steel is about 0.2836 pounds per cubic inch (490 lb/ft³), while aluminum is only about 0.0975 pounds per cubic inch (169 lb/ft³). That is why an aluminum part weighs roughly a third of the same part in steel.
Does this work for tube and pipe?
Yes. For round tube it subtracts the hollow inside area from the outside area before multiplying by length and density. For threaded pipe sized by nominal bore, use the dedicated pipe weight calculator, which works from the actual outside diameter and wall thickness.
Why does my supplier quote a slightly different weight?
Mills use nominal densities and rounded dimensions, and real bar has tolerances, mill scale, and coatings. Treat this as an accurate planning figure; exact shipping weight comes from the mill certificate.
Sources & references
This tool uses standard formulas and reference values from:
- • American Concrete Institute — ACI 318, Building Code Requirements for Structural Concrete. concrete.org
- • ICC — International Residential Code (IRC), span, footing and framing tables. codes.iccsafe.org
- • APA – The Engineered Wood Association, allowable span and load guidance.
Estimates for planning only. Span, load and code values vary by jurisdiction — verify against your local adopted code and a licensed engineer before building.