Aluminum 6061-T6 Rectangular Tube Weight
Mass per metre and per foot for aluminum 6061-t6 rectangular tube at 2,700 kg/m³ (ASTM B221 / B209 (T6 temper)). Every figure is for the section as drawn. A 6 m length of this size weighs 9.1 kg (20.5 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 1.523 kg/m (1.023 lb/ft). Against carbon steel's 7,850 kg/m³ that is -65.6 % — the same section in steel would be 4.427 kg/m.
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 2,700 kg/m³ that is 1.5228 kg/m for the reference size above.
AL 6061 rectangular tube — size series
| Depth | 1.5 | 2.0 | 3.0 | 4.0 | 5.0 | 6.0 |
|---|---|---|---|---|---|---|
| 20 mm | 0.219 kg/m · 0.147 lb/ft | 0.281 kg/m · 0.189 lb/ft | 0.389 kg/m · 0.261 lb/ft | 0.475 kg/m · 0.319 lb/ft | 0.540 kg/m · 0.363 lb/ft | 0.583 kg/m · 0.392 lb/ft |
| 25 mm | 0.279 kg/m · 0.188 lb/ft | 0.362 kg/m · 0.243 lb/ft | 0.510 kg/m · 0.343 lb/ft | 0.637 kg/m · 0.428 lb/ft | 0.742 kg/m · 0.499 lb/ft | 0.826 kg/m · 0.555 lb/ft |
| 30 mm | 0.340 kg/m · 0.229 lb/ft | 0.443 kg/m · 0.298 lb/ft | 0.632 kg/m · 0.425 lb/ft | 0.799 kg/m · 0.537 lb/ft | 0.945 kg/m · 0.635 lb/ft | 1.069 kg/m · 0.718 lb/ft |
| 40 mm | 0.462 kg/m · 0.310 lb/ft | 0.605 kg/m · 0.406 lb/ft | 0.875 kg/m · 0.588 lb/ft | 1.123 kg/m · 0.755 lb/ft | 1.350 kg/m · 0.907 lb/ft | 1.555 kg/m · 1.045 lb/ft |
| 50 mm | 0.583 kg/m · 0.392 lb/ft | 0.767 kg/m · 0.515 lb/ft | 1.118 kg/m · 0.751 lb/ft | 1.447 kg/m · 0.972 lb/ft | 1.755 kg/m · 1.179 lb/ft | 2.041 kg/m · 1.372 lb/ft |
| 60 mm | 0.705 kg/m · 0.474 lb/ft | 0.929 kg/m · 0.624 lb/ft | 1.361 kg/m · 0.914 lb/ft | 1.771 kg/m · 1.190 lb/ft | 2.160 kg/m · 1.451 lb/ft | 2.527 kg/m · 1.698 lb/ft |
| 80 mm | 0.948 kg/m · 0.637 lb/ft | 1.253 kg/m · 0.842 lb/ft | 1.847 kg/m · 1.241 lb/ft | 2.419 kg/m · 1.626 lb/ft | 2.970 kg/m · 1.996 lb/ft | 3.499 kg/m · 2.351 lb/ft |
| 100 mm | 1.191 kg/m · 0.800 lb/ft | 1.577 kg/m · 1.060 lb/ft | 2.333 kg/m · 1.568 lb/ft | 3.067 kg/m · 2.061 lb/ft | 3.780 kg/m · 2.540 lb/ft | 4.471 kg/m · 3.005 lb/ft |
| 120 mm | 1.434 kg/m · 0.963 lb/ft | 1.901 kg/m · 1.277 lb/ft | 2.819 kg/m · 1.894 lb/ft | 3.715 kg/m · 2.496 lb/ft | 4.590 kg/m · 3.084 lb/ft | 5.443 kg/m · 3.658 lb/ft |
| 150 mm | 1.798 kg/m · 1.208 lb/ft | 2.387 kg/m · 1.604 lb/ft | 3.548 kg/m · 2.384 lb/ft | 4.687 kg/m · 3.150 lb/ft | 5.805 kg/m · 3.901 lb/ft | 6.901 kg/m · 4.637 lb/ft |
| 200 mm | 2.406 kg/m · 1.617 lb/ft | 3.197 kg/m · 2.148 lb/ft | 4.763 kg/m · 3.200 lb/ft | 6.307 kg/m · 4.238 lb/ft | 7.830 kg/m · 5.262 lb/ft | 9.331 kg/m · 6.270 lb/ft |
Rows: depth (mm). Columns: wall thickness (mm). Computed for Aluminum 6061-T6 at 2700 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. Aluminum 6061-T6 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 aluminum 6061-t6
The general-purpose structural aluminium: magnesium and silicon alloyed, precipitation-hardened to T6, readily welded and machined. At 2,700 kg/m³ it is 2.91 times lighter than carbon steel, which is the entire reason it gets specified — but designers routinely forget that its modulus is also only about a third of steel’s, so a straight aluminium-for-steel swap cuts mass by 66 % while roughly tripling deflection for the same section. Weight savings and stiffness are separate problems.
- Density
- 2,700 kg/m³ = 0.0975 lb/in³ · 0.3439× carbon steel · typical spread ±1 %
- Specification
- ASTM B221 / B209 (T6 temper)
- Equivalents
- EN AW-6061 · JIS A6061 · GB 6061
- Typical uses
- Aircraft and drone frames · Marine decking and masts · Machine guards and jigs · Truck and trailer bodies
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
AL 6061 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 aluminum 6061-t6 rectangular tube weigh?
At the reference dimensions (a = 60 mm, b = 40 mm, t = 3 mm) a aluminum 6061-t6 rectangular tube of this size weighs 1.523 kg/m, or 1.023 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 aluminum 6061-t6's density of 2,700 kg/m³ gives 1.523 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 aluminum 6061-t6 weigh more or less than steel?
It is lighter than carbon steel for the same section — about 66 % lighter at 2,700 kg/m³. 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 0.3439× 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 al 6061 rectangular tube weigh the same as a al 6061 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.
Should I use AL 6061 weight or carbon steel weight for costing?
Use the material you are actually buying. At 2,700 kg/m³ against carbon steel's 7,850 kg/m³, the same rectangular tube differs by 65.6 % in mass. On a per-metre quote that is invisible; on a fabricated tonnage it is the difference between a margin and a loss. This page computes the steel figure as 4.427 kg/m for comparison.
Other materials, same rectangular tube
The same geometry in every material, so the only variable is density.
- Carbon steel rectangular tube — 7850 kg/m³
- SS 304 rectangular tube — 8000 kg/m³
- SS 316 rectangular tube — 8000 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 AL 6061 sections
The same density applied to every shape the site covers.
- AL 6061 round bar — A = π/4 · d²
- AL 6061 square bar — A = a²
- AL 6061 hexagonal bar — A = (√3/2) · AF² ≈ 0.8660 · AF²
- AL 6061 flat bar — A = w · t
- AL 6061 plate — A = w · t
- AL 6061 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 2,700 kg/m³ (ASTM B221 / B209 (T6 temper)). 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.