Weight Calculator

Metal Weight Calculator: Find Sheet, Section, Pipe and Steel Weight in Seconds

Metal weight calculation is the first step when preparing a bill of materials, planning transport or writing a quotation. At Vanox we work with steel, stainless steel and aluminum every day in expansion joint, piping and industrial installation projects. The free tool on this page gives the theoretical weight of the most common sections: sheet weight, section weight, pipe, square bar, angle, T, U and I sections, with millimetre precision. The guide below explains the formulas, worked examples, the effect of radius and common mistakes.

What Is Metal Weight Calculation and Why Is It Needed?

Metal weight calculation means finding the mass of a metal part from its geometry: the dimensions give the volume, and the volume multiplied by the density gives the mass. It underpins many site decisions: the total load of a steel structure, crane capacity, number of trucks, welding consumables and, above all, material cost. Steel prices are usually quoted per kilogram or ton, so an inaccurate weight can seriously distort a quotation.

Engineering offices often use tables or spreadsheets, but tables do not cover every size. For a custom-cut sheet, a non-standard box section or a different alloy you need to calculate again. The Vanox calculator handles this: enter the dimensions, choose the material and see the result in kilograms instantly. Calculations run in your browser; no registration is needed.

Basic Formula: Volume × Density

Weight (kg) = Cross-Section Area (mm²) × Length (mm) × Density (g/cm³) ÷ 1,000,000

The 1,000,000 factor comes from unit conversion. With dimensions in millimetres the volume is in mm³; dividing by 1,000 gives cm³, multiplying by the density in g/cm³ gives grams, and dividing by 1,000 again gives kilograms. The only difference between sections is how the cross-section area is found: a rectangle for sheet, a ring for pipe, two nested rectangles for box section, and a combination of rectangles for angle, T, U and I sections. When a radius is entered, the corner rounding is added or subtracted.

How to Calculate Sheet Weight

Sheet weight calculation is the most used calculation on this site. Whether it is black sheet, galvanized, stainless or aluminum plate, you need three dimensions: width, length and thickness. Select Sheet Plate, choose the material, enter the dimensions in millimetres and the quantity.

Sheet weight (kg) = Width × Length × Thickness × Density ÷ 1,000,000

Example: 1000 × 2000 × 2 mm black steel sheet

1000 × 2000 × 2 = 4,000,000 mm³. Multiplied by 7.86 and divided by 1,000,000 this gives 31.44 kg. Three such sheets weigh 94.32 kg. In aluminum (2.70) the same plate would weigh only 10.80 kg.

Quick sheet weight per square metre

For steel, 1 m² weighs the thickness in millimetres times 7.86. Use this table for a quick check:

Standard plate sizes of 1000 × 2000, 1250 × 2500 and 1500 × 3000 mm are 2, 3.125 and 4.5 m² respectively. For laser cutting, bending or flange work, remember scrap allowance: the net weight of a cut part differs from the gross weight of the plate you buy.

Section Weight Calculation: Box, Square, Angle, T, U and I

Section weight calculation needs a little more care because the geometry is more complex. The calculator asks for the relevant dimensions of each section and shows its cross-section drawing so you do not mix up which dimension is which.

Box section

Enter width (A), height (B), wall thickness (t) and length (L). The area is the outer rectangle minus the inner void. A 40 × 40 × 2 mm box section weighs about 2.39 kg per metre with no radius, and about 2.31 kg with a 4 mm outer corner radius, which matches market tables.

Square bar

For solid square bar the area is the side squared. A 20 × 20 mm bar weighs about 3.14 kg per metre. Hot-rolled bars can have slightly rounded corners, so an optional corner radius is provided.

Angle bar

Angle uses two leg sizes and the wall thickness; area = A × t + (B − t) × t. A 50 × 50 × 5 mm equal angle weighs about 3.73 kg per metre with sharp corners. Entering the inner corner radius adds the fillet area and brings the result closer to standard tables.

T, U and I sections

T, U and I sections are calculated as separate rectangles (flanges and web) and summed. For standard sections such as UPN, IPE, IPN, HEA and HEB the root radius between web and flange noticeably increases the area, so entering the catalogue r value gives a more accurate result. For tapered-flange sections like IPN and UPN the calculator assumes parallel flanges, so the result may deviate slightly from standard table values.

What Is Radius and Why Does It Affect Section Weight?

Radius is the rounding at the corner of a section. On cold-formed box sections the outer corners are rounded, meaning a little material is “missing” at the corner. On hot-rolled angle, U, T and I sections the inner corner, where web meets flange, has extra material. So radius reduces weight on box sections and increases it on angle and I sections.

In the Vanox calculator the radius field is optional. If left blank, a sharp corner is assumed and the result detail says “no radius”, so you always see the assumption used. If the entered radius is too large for the geometry, the tool warns you and shows the maximum allowed value. The effect is a few percent on small sections, but across hundreds of metres it can add up to hundreds of kilograms.

Pipe, Round Bar and Steel Weight

For pipe, enter outer diameter (D), wall thickness (t) and length (L). Area = π ÷ 4 × (D² − (D − 2t)²). A 60.3 × 3 mm steel pipe (DN50) has an area of about 540 mm², so a 6 m length weighs about 25.47 kg (4.24 kg/m). When adding expansion joints, flanges or valves to a pipeline, include their weight in the total load for hanger and support selection.

For solid round bar only diameter and length are needed: a Ø20 mm steel bar weighs about 2.47 kg per metre. The same logic applies to rebar, where Ø × Ø × 0.00617 gives kg/m. For hex bar, use the across-flats size (S); area = 0.866 × S².

Material Densities: Steel, Stainless, Aluminum and More

Density is the only thing that makes two parts of the same size differ in weight. The representative values used in the calculator:

Stainless grades such as 304 and 316 are typically 7.90–8.00 g/cm³, and aluminum alloys range from 2.66 to 2.80. For critical calculations use the density on the manufacturer’s material certificate.

Common Mistakes in Weight Calculation

• Unit confusion: Entering length in metres and section in millimetres is off by 1,000×. All dimensions in the tool are millimetres; type 6000 for 6 metres.
• Mixing wall thickness with diameter: If the inner diameter is known, wall thickness = (outer − inner) ÷ 2.
• Ignoring radius: On large orders the difference can reach hundreds of kilograms. Enter it if known; otherwise note the result is without radius.
• Wrong material: Choosing aluminum instead of stainless cuts the weight to about one third. Check the material box first.
• Forgetting scrap: Cutting, hole and bending scrap do not appear in theoretical weight. Add an allowance when purchasing.
• Ignoring coating: Hot-dip galvanizing can add roughly 3–8% to the weight.

Advantages of the Vanox Metal Weight Calculator

Vanox manufactures metal and rubber expansion joints, earthquake and dilatation joints and installation equipment for industrial plants. This tool makes the calculation methods our engineering team uses every day available to everyone. It offers ten section types, eight materials and an optional radius on a single screen, and works on mobile, so you can check weights on site, in the warehouse or in a customer meeting.

Because every calculated item is added to the list, you can build up a project’s metal requirement piece by piece, see the total tonnage and plan transport. The values are theoretical; for final purchasing and shipping decisions use manufacturer tables and weighing results. If your project needs equipment for pipeline expansion, vibration or seismic movement, see our products above or contact the Vanox team.

Frequently Asked Questions About Metal Weight Calculation