About the Metal Weight Calculator
This metal weight calculator estimates how much a piece of metal stock weighs. Choose the material and the shape — plate or sheet, round, square or hex bar, round tube, rectangular tube or angle — then enter the dimensions, the length and the number of pieces. It returns the total weight in pounds and kilograms, the weight of each piece, the weight per foot and per metre, and the volume.
Fabricators, machinists, welders, purchasers and engineers use it to quote material, plan lifting and shipping, check a supplier’s weight-per-foot figure or compare a steel design with an aluminum one. The comparison chart shows what the same piece would weigh in other common metals.
Weight is simply volume × density. Densities are typical handbook values (carbon steel 7.85 g/cm³, aluminum 6061 2.70 g/cm³, 304 stainless about 8.0 g/cm³); real alloys vary by a percent or two, and rolled sections with rounded corners weigh slightly less than the sharp-cornered geometry used here. Enter all dimensions in inches or all in millimetres.
How to use the metal weight calculator
- 1Choose the metal, or pick custom and enter a density in g/cm³.
- 2Select the shape of the stock.
- 3Choose inches or millimetres and enter every dimension in that unit, including length.
- 4Enter how many pieces you need.
- 5Read the total weight, weight per piece and weight per foot or metre.
Formula and method
The calculator works out the cross-sectional area of the chosen shape, multiplies by the length to get volume, and multiplies by the metal’s density. Dimensions are converted to centimetres first, so volume is in cm³ and density in g/cm³ gives grams; the result is converted to kilograms and pounds (1 kg = 2.20462 lb).
Shapes are treated as sharp-cornered: a rectangular tube is the outer rectangle minus the inner one, an angle is two overlapping legs minus the shared corner square, and a hex bar uses the across-flats size. Weight per foot and per metre is the area × density for a 1 ft or 1 m length, which is how steel suppliers list bar and tube.
- W
- Total weight
- A
- Cross-sectional area
- L
- Length of each piece
- ρ
- Density of the metal (g/cm³)
- d, D
- Diameter / outside diameter
- t
- Thickness or wall thickness
- s
- Hex size across flats
Worked examples
4 × 8 ft sheet of 1/4" steel plate
The plate is 48 × 96 × 0.25 in = 1,152 in³, or 18,878 cm³. At 7.85 g/cm³ that is 148.2 kg, or about 326.7 lb — the familiar 10.2 lb per square foot for 1/4" plate.
1" aluminum 6061 round bar, 12 ft, 5 pieces
A 1" round bar has an area of 0.7854 in² (5.067 cm²). One 144 in bar is 113.1 in³ = 1,853 cm³, which at 2.70 g/cm³ is 5.00 kg or 11.0 lb. Five bars weigh about 55.2 lb, roughly 0.92 lb per foot.
Stainless round tube, 50.8 mm OD × 2 mm wall × 6 m
The tube area is π/4 × (50.8² − 46.8²) = 306.6 mm² (3.066 cm²). Multiplying by 8.0 g/cm³ gives 2.45 kg per metre, so a 6 m length weighs about 14.7 kg (32.5 lb).
Frequently asked questions
How do you calculate the weight of metal?+
Multiply the volume of the piece by the density of the metal. For a plate, volume is length × width × thickness; for a bar or tube, it is the cross-section area × length. Steel weighs about 0.2836 lb per cubic inch (7.85 g/cm³).
How much does a 4×8 sheet of steel weigh?+
A 4 × 8 ft sheet of 1/4" mild steel plate weighs about 327 lb (148 kg). A 1/8" sheet weighs about 163 lb, and 16-gauge sheet (0.0598") about 78 lb.
Is aluminum lighter than steel?+
Yes. Aluminum alloys have a density of about 2.70 g/cm³ versus 7.85 g/cm³ for carbon steel, so an aluminum part weighs about 34% of an identical steel part — roughly one third.
Does stainless steel weigh more than carbon steel?+
Slightly. Austenitic stainless steels such as 304 and 316 have a density of about 7.9–8.0 g/cm³, around 1–2% heavier than carbon steel at 7.85 g/cm³.
Why does my supplier’s weight differ slightly?+
Suppliers often use rounded corners, nominal versus actual sizes, mill tolerances and slightly different alloy densities. Structural tubes and angles have corner radii that remove a little material, so published weights can be 1–3% lower than sharp-corner geometry.