Pick a profile (plate, round bar, tube, angle and more), choose the metal, type in the size, and get the weight in kilograms and pounds. It also gives weight per metre, a total for several pieces, and an optional cost. Free, private, and runs entirely in your browser.
Nominal sizes only. Rounded corners, coatings and mill tolerances can change the real weight by a few percent.
Every metal weight calculation follows the same three steps: find the cross-section area of the profile, multiply it by the length to get the volume, then multiply the volume by the density of the metal. This calculator does all three for you and shows your own numbers in the working line under the result.
The cross-section area depends on the profile:
A round steel bar has a diameter of 20 mm and a length of 1 m. Its area is π × 0.02² ÷ 4 = 0.000314 m². The volume is 0.000314 m³, and with a steel density of 7,850 kg/m³ the weight is about 2.47 kg. A handy shortcut for steel round bar is weight per metre ≈ d² ÷ 162, with d in millimetres. For 20 mm that gives 400 ÷ 162 ≈ 2.47 kg/m, the same answer.
For plate and sheet, weight per square metre is just thickness times density. These values assume the densities used by the calculator.
| Thickness | Steel | Stainless steel | Aluminum | Copper | Brass |
|---|---|---|---|---|---|
| 1 mm | 7.85 kg/m² | 8.00 kg/m² | 2.70 kg/m² | 8.96 kg/m² | 8.50 kg/m² |
| 2 mm | 15.70 kg/m² | 16.00 kg/m² | 5.40 kg/m² | 17.92 kg/m² | 17.00 kg/m² |
| 3 mm | 23.55 kg/m² | 24.00 kg/m² | 8.10 kg/m² | 26.88 kg/m² | 25.50 kg/m² |
| 5 mm | 39.25 kg/m² | 40.00 kg/m² | 13.50 kg/m² | 44.80 kg/m² | 42.50 kg/m² |
| 10 mm | 78.50 kg/m² | 80.00 kg/m² | 27.00 kg/m² | 89.60 kg/m² | 85.00 kg/m² |
How do I calculate the weight of a steel bar? Multiply the cross-section area by the length to get the volume, then multiply by the density of steel, about 7,850 kg/m³. A 20 mm round steel bar that is 1 m long weighs about 2.47 kg.
What density should I use for steel, aluminum and copper? Common handbook values are about 7,850 kg/m³ for carbon steel, 8,000 kg/m³ for stainless steel, 2,700 kg/m³ for aluminum and 8,960 kg/m³ for copper. Real alloys vary by a percent or two.
How much does a steel plate weigh per square metre? A 1 mm steel plate weighs about 7.85 kg per square metre, so the weight scales with thickness: 10 mm is about 78.5 kg per square metre.
Is the weight of an angle or tube exact? It is a close estimate. The calculator uses the nominal size and ignores rounded corners and manufacturing tolerances, so mill-certified weights can differ slightly.
Can I use inches and feet? Yes. Choose mm, cm, m, in or ft for the dimensions, and read the result in both kilograms and pounds.
Weighing metal by calculation is older than modern steelmaking. Merchants and builders have long relied on tables of weights per unit length or area because lifting and shipping costs depend on weight. After Henry Bessemer patented his converter process in 1856, steel became cheap enough to use in bridges, rails and buildings, and standard sections such as angles, channels and beams spread across engineering. Today each section has a published mass per metre, which is the same number this calculator derives from the shape and the density.
Use it to estimate the weight of a delivery before it arrives, check whether a part is light enough for a hoist or a shelf, compare the cost of aluminum against steel for the same part, or find how much a fabricated frame will weigh. For solid shapes that are not in the list, such as a sphere, cone or torus, the 3D Shape Calculator also gives weight by material, and the Density Calculator helps when you only know a sample's mass and volume.