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Metal Weight Calculator: Sheet, Pipe, Angle, Channel, I-beam and Rebar
The metal calculator works out the weight of rolled metal from its dimensions: sheet, flat bar, round bar, rebar, pipe, hollow section, angle, channel and I-beam. Choose the metal and the section, enter the dimensions and quantity, and you get the mass of one piece, the mass per metre and the total mass in kilograms and tonnes. Nothing is sent anywhere.
Contents
Rolled metal weight calculator
The calculator gives a calculated mass from nominal dimensions. For steel, the result also shows the approximate cost of hot-dip galvanising for that mass.
List of items
| Item | Qty | Mass, kg |
|---|
This is a calculated mass from nominal dimensions. The actual mass depends on the rolling tolerances, so check the supplier's documents for ordering and accounting.
Request a calculationHow to use it
- choose the metal: steel, stainless steel, aluminium, copper or brass; for another alloy enter your own density;
- choose the section and enter the dimensions in millimetres; the length of a sheet is given in millimetres and the length of other products in metres; angle, channel, I-beam and rebar sizes are picked from a list;
- enter the quantity: the calculator shows the mass of one piece, the mass per metre (or per m² of sheet), the total mass and how many metres or square metres of the product make one tonne;
- the “Add to the list” button collects several items and adds up their total mass.
How the mass is calculated
The mass of a rolled product is its volume multiplied by the density. For long products it is convenient to start from the cross-sectional area: the mass per metre in kilograms equals the area in mm² multiplied by the density in kg/m³ and by 0.000001. For steel (7850 kg/m³) that is 0.00785 kg for every square millimetre of the section.
Sheet is calculated by area: the mass per m² in kilograms equals the thickness in millimetres multiplied by the density and divided by 1000. A steel sheet 10 mm thick weighs 78.5 kg per square metre.
| Section | Cross-sectional area, mm² | Mass of 1 m of steel, kg |
|---|---|---|
| Flat bar | b × t | 0.00785 × b × t |
| Round bar, rebar | 0.7854 × d² | 0.006165 × d² |
| Square bar | a² | 0.00785 × a² |
| Hexagon bar | 0.866 × s² | 0.006798 × s² |
| Round pipe | 3.1416 × (D − t) × t | 0.02466 × (D − t) × t |
| Hollow section | 2t × (a + b − 2t) minus a correction for the corner radii | 0.00785 × area |
| Equal angle | d × (2b − d) plus a correction for the radii given in the range | 0.00785 × area |
| Channel, I-beam | from the section table | the table value for the section number |
Symbols: t is the thickness, d the diameter, D the outer diameter, a and b the sides, s the size across flats. All dimensions are in millimetres.
Density of metals
The calculator takes the density from a list. These are reference values: a particular alloy grade has a slightly different density. If you know the exact one, choose “Other density” and enter it.
| Metal | Density, kg/m³ |
|---|---|
| Steel (St3, S245, S345, 09G2S) | 7850 |
| Stainless steel | 7900 |
| Aluminium | 2700 |
| Copper | 8940 |
| Brass | 8500 |
Calculation examples
All examples are for steel with a density of 7850 kg/m³.
| Product | Mass per 1 m or 1 m² | Mass of the product |
|---|---|---|
| Sheet 10 × 1500 × 6000 mm | 78.5 kg/m² | 706.5 kg |
| Round pipe 57 × 3.5 mm, 6 m long | 4.618 kg/m | 27.71 kg |
| Hollow section 40 × 40 × 3 mm, 6 m long | 3.303 kg/m | 19.82 kg |
| Angle 50 × 5 mm, 6 m long | 3.769 kg/m | 22.61 kg |
| Channel No. 12, 6 m long | 10.4 kg/m | 62.4 kg |
| Rebar Ø12 mm, 12 m long | 0.888 kg/m | 10.65 kg |
The calculator takes the mass of channels and I-beams from the section table and calculates the rest by the formulas.
Mass of 1 m of rebar and round steel
A table for a quick estimate of bar products. The values are for steel; for another metal, multiply the mass by the ratio of the densities.
| Diameter, mm | Mass of 1 m, kg | Metres in 1 tonne |
|---|---|---|
| 6 | 0.222 | 4505 |
| 8 | 0.395 | 2534 |
| 10 | 0.617 | 1622 |
| 12 | 0.888 | 1126 |
| 14 | 1.208 | 828 |
| 16 | 1.578 | 634 |
| 18 | 1.998 | 501 |
| 20 | 2.466 | 405 |
| 22 | 2.984 | 335 |
| 25 | 3.853 | 260 |
| 28 | 4.834 | 207 |
| 32 | 6.313 | 158 |
| 36 | 7.990 | 125 |
| 40 | 9.865 | 101 |
What the calculator does not take into account
- tolerances: rolled metal is made with deviations in size and thickness, so the actual mass differs slightly from the calculated one;
- the corner radii of hollow sections: the calculator uses typical values (2t for walls up to 6 mm, 2.5t up to 10 mm, 3t above 10 mm), while in a real tube the radius depends on the manufacturer;
- coatings, welds, holes and offcuts: all of them change the mass of the finished product;
- other series of channels and I-beams: for them choose “Section by mass per metre” and enter the mass from the section table.
From mass to cost
Mass is the basis for working out the cost. Hot-dip galvanising is charged per kilogram, so the galvanising cost calculator accepts the mass from this calculator. Steel fabrication is priced per tonne; the article How much steel fabrication costs explains it in detail.
The mass of the metal can also be seen in the drawings: a set of KMD drawings contains a metal take-off from which the mass of the structure is visible, as the article What is KMD describes. To order steel fabrication to drawings, send them with your request. The tables of masses and dimensions of standard sections are collected in the rolled metal handbook.
Updated:
Metal weight calculator: frequently asked questions
How do I calculate the weight of rolled metal?
Multiply the cross-sectional area by the length and by the density of the metal. For steel, the mass of 1 m in kilograms equals the area in mm² multiplied by 0.00785. The calculator does it for you: you only choose the section and enter the dimensions.
What is the density of steel, aluminium and copper?
Steel is 7850 kg/m³, aluminium 2700 kg/m³ and copper 8940 kg/m³. These are reference values; a particular alloy grade differs slightly.
How much does 1 metre of 12 mm rebar weigh?
0.888 kg. So one tonne holds about 1126 m of such rebar.
How do I find how many metres of pipe or rebar there are in a tonne?
Divide 1000 kg by the mass of 1 m. The calculator shows this result in the “In 1 tonne” line.
How does the calculated weight differ from the actual one?
The calculator works from nominal dimensions, while real rolled metal has tolerances in size and thickness. So the actual mass differs slightly: for ordering and accounting, check the supplier’s documents.
Which sections does the calculator include?
Sheet, flat bar, round bar, square bar, hexagon bar, rebar, round pipe and hollow section, equal angle with a leg from 20 to 250 mm, channel No. 5–40 and I-beam No. 10–60 of the ordinary range. Other series, for example I-beams with parallel flange faces, can be entered through “Section by mass per metre”.
Does the calculator save my data?
No. Everything is calculated in your browser and nothing is sent anywhere. The list of items disappears when the page is refreshed.
Related products: Custom steel fabrication · Hot-dip galvanising · Steel structure design (structural and detail drawings)
More on this topic: Quality Control of Steel Structures: From Incoming Metal to Zinc Coating · How Much Do Steel Structures Cost: Price per Tonne and What Drives It
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