How to use the metal weight calculator (steel, aluminum)
- Choose the shape: plate or sheet, flat bar, round bar, square bar, round tube or pipe, or rectangular tube.
- Choose the metal. If you know your supplier's density, enter it in the override box.
- Choose a unit, then enter the length and the other dimensions the shape needs, such as width, thickness or wall, and diameter.
- Enter the number of pieces and read the weight in pounds and kilograms, with the weight per foot of length.
Formula
Volume = cross-section area x length
Plate or flat bar area = width x thickness
Round bar area = pi x diameter^2 / 4; square bar area = side^2
Tube area = outside area - inside area
Weight = volume x density
One inch is exactly 25.4 mm and one pound is exactly 0.45359237 kg. Densities are example reference values in kilograms per cubic meter, not from a single cited source.
Worked example
A carbon steel plate 48 by 24 inches and 0.25 inch thick has a volume of 288 cubic inches. At 7,850 kg/m3 that weighs 37.05 kg, or 81.68 lb (81.677 lb).
The same plate in aluminum (2,700 kg/m3) weighs 12.74 kg. A 1 inch round steel bar, 48 inches long has an area of 0.7854 sq in and weighs about 4.85 kg (10.69 lb). A 2 inch round tube with a 0.25 inch wall has a cross-section of 1.3744 sq in, or about 4.68 lb per foot in steel.
Densities and alloys
The table lists example reference densities for carbon steel (7,850 kg/m3), stainless 304 (8,000), aluminum 6061 (2,700), copper (8,960), brass (8,500), cast iron (7,200), titanium (4,500), zinc (7,140) and lead (11,340). These are example reference values and were not taken from one cited source, and the real density of an alloy varies with its composition. Use the override when you have the figure from a supplier or a mill certificate.
Why a calculated weight is not a shipping weight
Real stock has tolerances in thickness, rounded corners on bars and tubes, and mill scale or coatings. Sheet metal gauges are not the same across metals. For quotes, freight and lifting plans, use the weight that the supplier states. For other volumes and shapes use the volume calculator, and for lumber use the board foot calculator.
Unit tips
Enter all dimensions in the same unit. Use millimeters for metric stock sizes and inches for U.S. stock. For rebar, see the rebar calculator, which works from bar sizes, and for other conversions use the unit converter.
Assumptions and limits
- Densities are example reference values and are not exact for every alloy or supplier. They are editable through the override.
- The shape is a perfect prism. Rounded corners, tolerances and coatings are ignored.
- Tubes and pipes use the outside size and wall thickness you enter, not a nominal pipe size.
- The pound-kilogram conversion uses 1 lb = 0.45359237 kg.
Frequently asked questions
How do I calculate the weight of a steel plate?
Multiply length, width and thickness to get the volume, then multiply by the density of steel, about 7,850 kg per cubic meter.
How much does a cubic foot of steel weigh?
About 490 pounds using the example density of 7,850 kg/m3 for carbon steel. Aluminum is about 169 pounds per cubic foot.
Is stainless steel heavier than carbon steel?
Slightly. The example density of stainless 304 is about 8,000 kg per cubic meter against about 7,850 for carbon steel.
How do I find the weight of a pipe?
Use the round tube shape with the outside diameter and wall thickness. Nominal pipe sizes are not the same as the outside diameter.