Carbon Steel Rectangular Tube Weight
Mass per metre and per foot for carbon steel rectangular tube at 7,850 kg/m³ (ASTM A36 / AISI 1018 / EN 10025 S275). Every figure is for the section as drawn. A 6 m length of this size weighs 26.6 kg (59.5 lb per 20 ft).
At the reference dimensions (a = 60 mm, b = 40 mm, t = 3 mm) this section has a cross-sectional area of 564.0 mm², giving 4.427 kg/m (2.975 lb/ft). This is the baseline density, so the figures here are what a steel weight chart shows.
Rectangular Tube — formula and derivation
Area of a rectangular tube
A = a·b − (a − 2t)(b − 2t)
A = a·b − (a − 2t)(b − 2t), which expands to A = 2t(a + b) − 4t²
Worked through with the default dimensions:
A = a·b − (a − 2t)(b − 2t)Outer = 60 × 40 = 2400.0 mm²Inner = 54.0 × 34.0 = 1836.0 mm²A = 2400.0 − 1836.0A = 564.0 mm²
- a
- Depth
- b
- Width
- t
- Wall thickness
Weight follows from the area with no further geometry: m = A × 10⁻⁶ × ρ, where A is in mm², ρ in kg/m³ and m in kg/m. At 7,850 kg/m³ that is 4.4274 kg/m for the reference size above.
Carbon steel rectangular tube — size series
| Depth | 1.5 | 2.0 | 3.0 | 4.0 | 5.0 | 6.0 |
|---|---|---|---|---|---|---|
| 20 mm | 0.636 kg/m · 0.427 lb/ft | 0.816 kg/m · 0.549 lb/ft | 1.130 kg/m · 0.760 lb/ft | 1.382 kg/m · 0.928 lb/ft | 1.570 kg/m · 1.055 lb/ft | 1.696 kg/m · 1.139 lb/ft |
| 25 mm | 0.812 kg/m · 0.546 lb/ft | 1.052 kg/m · 0.707 lb/ft | 1.484 kg/m · 0.997 lb/ft | 1.853 kg/m · 1.245 lb/ft | 2.159 kg/m · 1.451 lb/ft | 2.402 kg/m · 1.614 lb/ft |
| 30 mm | 0.989 kg/m · 0.665 lb/ft | 1.287 kg/m · 0.865 lb/ft | 1.837 kg/m · 1.234 lb/ft | 2.324 kg/m · 1.561 lb/ft | 2.748 kg/m · 1.846 lb/ft | 3.109 kg/m · 2.089 lb/ft |
| 40 mm | 1.342 kg/m · 0.902 lb/ft | 1.758 kg/m · 1.182 lb/ft | 2.543 kg/m · 1.709 lb/ft | 3.266 kg/m · 2.194 lb/ft | 3.925 kg/m · 2.637 lb/ft | 4.522 kg/m · 3.038 lb/ft |
| 50 mm | 1.696 kg/m · 1.139 lb/ft | 2.229 kg/m · 1.498 lb/ft | 3.250 kg/m · 2.184 lb/ft | 4.208 kg/m · 2.827 lb/ft | 5.103 kg/m · 3.429 lb/ft | 5.935 kg/m · 3.988 lb/ft |
| 60 mm | 2.049 kg/m · 1.377 lb/ft | 2.700 kg/m · 1.815 lb/ft | 3.956 kg/m · 2.659 lb/ft | 5.150 kg/m · 3.460 lb/ft | 6.280 kg/m · 4.220 lb/ft | 7.348 kg/m · 4.937 lb/ft |
| 80 mm | 2.755 kg/m · 1.852 lb/ft | 3.642 kg/m · 2.448 lb/ft | 5.369 kg/m · 3.608 lb/ft | 7.034 kg/m · 4.726 lb/ft | 8.635 kg/m · 5.802 lb/ft | 10.174 kg/m · 6.836 lb/ft |
| 100 mm | 3.462 kg/m · 2.326 lb/ft | 4.584 kg/m · 3.081 lb/ft | 6.782 kg/m · 4.558 lb/ft | 8.918 kg/m · 5.992 lb/ft | 10.990 kg/m · 7.385 lb/ft | 13.000 kg/m · 8.735 lb/ft |
| 120 mm | 4.168 kg/m · 2.801 lb/ft | 5.526 kg/m · 3.714 lb/ft | 8.195 kg/m · 5.507 lb/ft | 10.802 kg/m · 7.258 lb/ft | 13.345 kg/m · 8.967 lb/ft | 15.826 kg/m · 10.634 lb/ft |
| 150 mm | 5.228 kg/m · 3.513 lb/ft | 6.939 kg/m · 4.663 lb/ft | 10.315 kg/m · 6.931 lb/ft | 13.628 kg/m · 9.157 lb/ft | 16.878 kg/m · 11.341 lb/ft | 20.065 kg/m · 13.483 lb/ft |
| 200 mm | 6.994 kg/m · 4.700 lb/ft | 9.294 kg/m · 6.246 lb/ft | 13.847 kg/m · 9.305 lb/ft | 18.338 kg/m · 12.322 lb/ft | 22.765 kg/m · 15.297 lb/ft | 27.130 kg/m · 18.230 lb/ft |
Rows: depth (mm). Columns: wall thickness (mm). Computed for Carbon Steel at 7850 kg/m³.
| Depth | 1.5 | 2.0 | 3.0 | 4.0 | 5.0 | 6.0 |
|---|---|---|---|---|---|---|
| 20 mm | 81.0 | 104.0 | 144.0 | 176.0 | 200.0 | 216.0 |
| 25 mm | 103.5 | 134.0 | 189.0 | 236.0 | 275.0 | 306.0 |
| 30 mm | 126.0 | 164.0 | 234.0 | 296.0 | 350.0 | 396.0 |
| 40 mm | 171.0 | 224.0 | 324.0 | 416.0 | 500.0 | 576.0 |
| 50 mm | 216.0 | 284.0 | 414.0 | 536.0 | 650.0 | 756.0 |
| 60 mm | 261.0 | 344.0 | 504.0 | 656.0 | 800.0 | 936.0 |
| 80 mm | 351.0 | 464.0 | 684.0 | 896.0 | 1,100.0 | 1,296.0 |
| 100 mm | 441.0 | 584.0 | 864.0 | 1,136.0 | 1,400.0 | 1,656.0 |
| 120 mm | 531.0 | 704.0 | 1,044.0 | 1,376.0 | 1,700.0 | 2,016.0 |
| 150 mm | 666.0 | 884.0 | 1,314.0 | 1,736.0 | 2,150.0 | 2,556.0 |
| 200 mm | 891.0 | 1,184.0 | 1,764.0 | 2,336.0 | 2,900.0 | 3,456.0 |
Area is a property of the geometry alone, so this table is the same for every material. It is what you enter into a stress calculation; the mass table is what you enter into an order.
Each row is one nominal size. Because the area is computed from your dimensions rather than read from a mill table, a non-standard size is just as accurate — put it into the calculator above rather than interpolating between rows.
The same rectangular tube in every material
Geometry is fixed and only density changes, so this table is the whole material-selection question in one view. Carbon Steel is highlighted. The percentage column is against carbon steel, which is the figure most quotations are built on.
| Material | Density kg/m³ | lb/in³ | Mass / length kg/m | lb/ft | vs carbon steel |
|---|---|---|---|---|---|
| Carbon Steel | 7,850 | 0.2836 | 4.427 | 2.975 | +0.0 % |
| Stainless Steel 304 | 8,000 | 0.2890 | 4.512 | 3.032 | +1.9 % |
| Stainless Steel 316 | 8,000 | 0.2890 | 4.512 | 3.032 | +1.9 % |
| Stainless Steel 316L | 8,000 | 0.2890 | 4.512 | 3.032 | +1.9 % |
| Stainless Steel 430 | 7,700 | 0.2782 | 4.343 | 2.918 | -1.9 % |
| Aluminum 6061-T6 | 2,700 | 0.0975 | 1.523 | 1.023 | -65.6 % |
| Aluminum 5052-H32 | 2,680 | 0.0968 | 1.512 | 1.016 | -65.9 % |
| Aluminum 7075-T6 | 2,810 | 0.1015 | 1.585 | 1.065 | -64.2 % |
| Copper C11000 | 8,940 | 0.3230 | 5.042 | 3.388 | +13.9 % |
| Brass C36000 | 8,500 | 0.3071 | 4.794 | 3.221 | +8.3 % |
| Bronze C93200 | 8,800 | 0.3179 | 4.963 | 3.335 | +12.1 % |
| Titanium Grade 2 | 4,510 | 0.1629 | 2.544 | 1.709 | -42.5 % |
| Gray Cast Iron | 7,200 | 0.2601 | 4.061 | 2.729 | -8.3 % |
| Lead | 11,340 | 0.4097 | 6.396 | 4.298 | +44.5 % |
| Rigid PVC (Type I) | 1,400 | 0.0506 | 0.790 | 0.531 | -82.2 % |
| HDPE (PE 100) | 960 | 0.0347 | 0.541 | 0.364 | -87.8 % |
Same geometry throughout, so the only variable is density. Carbon steel is highlighted as the baseline.
A note on using this table for costing: mass is not price. Aluminium is roughly a third of steel's mass here, but per kilogram it costs several times more, so a straight swap rarely saves money — what it buys is reduced load on a structure or a vehicle.
About carbon steel
The baseline against which every other metal is compared. Mild and medium carbon steels sit at 7,850 kg/m³ across the usual structural and free-machining grades: A36 plate, 1018 shaft, S275JR section. Carbon content moves density so little over the 0.05–0.60 % range that one figure covers the family, which is why mill weight tables for "steel" almost always assume 7,850 kg/m³ (0.2836 lb/in³). Use this entry when the drawing says "steel" and no grade is called out.
- Density
- 7,850 kg/m³ = 0.2836 lb/in³ · 1.0000× carbon steel · typical spread ±1 %
- Specification
- ASTM A36 / AISI 1018 / EN 10025 S275
- Equivalents
- AISI 1018 · EN 1.0401 · JIS SS400 · GB Q235
- Typical uses
- Structural sections · Plate and bar stock · Fabricated weldments · Shafts and pins
Unprotected carbon steel corrodes at roughly 0.1 mm/year in a mild inland atmosphere and far faster in coastal or chemical service, so a corrosion allowance changes the mass you should order — not this density.
About rectangular tube
Rectangular tube is the shape to reach for when a beam has to be shallower than it is wide in one direction only. Because depth drives bending stiffness far more than width does, taking a rectangular section and turning it 90° changes the stiffness dramatically while the weight stays identical — a 100 × 50 × 4 tube is about 4 times stiffer about its strong axis than its weak axis, at 9.10 kg/m either way. The table here holds the common 2:1 depth-to-width proportion; enter your own dimensions in the calculator when the section is not 2:1.
Specified as depth × width × wall thickness. Confirm which dimension is the depth on a drawing before computing loads.
Download this data
Carbon steel rectangular tube — CSV
Both buttons below read the tables rendered on this page, so the file matches what you are looking at. The full catalogue — all 16 materials across all 10 sections — is on the downloads page.
Fields are quoted per RFC 4180, with a UTF-8 byte-order mark so Excel reads the mm² and · characters correctly. Blank lines separate the weight matrix from the area matrix.
Frequently asked questions
How much does carbon steel rectangular tube weigh?
At the reference dimensions (a = 60 mm, b = 40 mm, t = 3 mm) a carbon steel rectangular tube of this size weighs 4.427 kg/m, or 2.975 lb/ft. The table above lists the figure for every standard size so you can read your size directly instead of scaling.
How is the weight of rectangular tube calculated?
Weight is cross-sectional area × length × density. For this shape the area is A = a·b − (a − 2t)(b − 2t). At the reference dimensions that gives 564.0 mm², and multiplying by carbon steel's density of 7,850 kg/m³ gives 4.427 kg/m. Nothing is looked up in a table — which is why a non-standard size is calculated just as accurately as a standard one.
Why does carbon steel weigh more or less than steel?
It is the 7,850 kg/m³ baseline that every other figure on this site is measured against. Density is the only variable: the cross-sectional area depends purely on geometry, so a rectangular tube of the same dimensions has the same area in every material and the mass simply scales with density. In this case the ratio is 1.0000× carbon steel.
What is the cross-sectional area of a rectangular tube?
The area depends only on the dimensions, not on the material, so it is identical whichever material you select: at the reference dimensions it is 564.0 mm² (0.8742 in²). That is the number you would enter into a stress or deflection calculation, and it is why changing material on this page never changes the area column.
Does a carbon steel rectangular tube weigh the same as a carbon steel part of a different shape?
No, and the difference is larger than most people expect. At equal nominal size, a square bar is 27.3 % heavier than a round bar, and a hollow section is typically 60–80 % lighter than the solid bar it replaces. Weight follows area, and area changes faster than dimensions do — which is exactly why this needs calculating rather than estimating.
Other materials, same rectangular tube
The same geometry in every material, so the only variable is density.
- SS 304 rectangular tube — 8000 kg/m³
- SS 316 rectangular tube — 8000 kg/m³
- AL 6061 rectangular tube — 2700 kg/m³
- Copper rectangular tube — 8940 kg/m³
- Brass rectangular tube — 8500 kg/m³
- HDPE rectangular tube — 960 kg/m³
- PVC rectangular tube — 1400 kg/m³
- AL 5052 rectangular tube — 2680 kg/m³
Other Carbon steel sections
The same density applied to every shape the site covers.
- Carbon steel round bar — A = π/4 · d²
- Carbon steel square bar — A = a²
- Carbon steel hexagonal bar — A = (√3/2) · AF² ≈ 0.8660 · AF²
- Carbon steel flat bar — A = w · t
- Carbon steel plate — A = w · t
- Carbon steel round tube — A = π/4 · (D² − d²), d = D − 2t
Reference data and tools
- Metal weight overview — how the calculation works
- All 16 materials — densities and specifications
- All 10 sections — formulas and size series
- Density chart — lightest to heaviest
- Metal weight calculator — any size, any material
- All calculators — metal weight and pipe weight
- Download the data — CSV, generated from the same source
- Cross-reference tables — DN / NPS / material equivalents
- Methodology and sources — where every number comes from
Rectangular Tube area from A = a·b − (a − 2t)(b − 2t). Mass computed as area × length × density at 7,850 kg/m³ (ASTM A36 / AISI 1018 / EN 10025 S275). No weight on this page is copied from a published table — which is why figures can differ in the last significant digit from a mill's chart calculated at a nominal density.
- Elementary plane geometry. The circle, polygon and hollow-section area formulas.
- ASTM material specifications for each grade named in the material entry (A36, A240/A276, B209/B211/B221, B152/B16/B505, B265/B348, A48, B29, D1784, D3350).
- BIPM / NIST definitional constants: international inch = 25.4 mm, foot = 0.3048 m, pound = 0.45359237 kg.
Dataset version 2026.09.1 · dimensions last verified against source 2026-09-21. Found an error? Report it — corrections are issued with a version bump.