Stainless Steel 316 Rectangular Tube Weight
Mass per metre and per foot for stainless steel 316 rectangular tube at 8,000 kg/m³ (ASTM A240 / A276 (UNS S31600)). Every figure is for the section as drawn. A 6 m length of this size weighs 27.1 kg (60.6 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 4.512 kg/m (3.032 lb/ft). Against carbon steel's 7,850 kg/m³ that is +1.9 % — 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 8,000 kg/m³ that is 4.5120 kg/m for the reference size above.
SS 316 rectangular tube — size series
| Depth | 1.5 | 2.0 | 3.0 | 4.0 | 5.0 | 6.0 |
|---|---|---|---|---|---|---|
| 20 mm | 0.648 kg/m · 0.435 lb/ft | 0.832 kg/m · 0.559 lb/ft | 1.152 kg/m · 0.774 lb/ft | 1.408 kg/m · 0.946 lb/ft | 1.600 kg/m · 1.075 lb/ft | 1.728 kg/m · 1.161 lb/ft |
| 25 mm | 0.828 kg/m · 0.556 lb/ft | 1.072 kg/m · 0.720 lb/ft | 1.512 kg/m · 1.016 lb/ft | 1.888 kg/m · 1.269 lb/ft | 2.200 kg/m · 1.478 lb/ft | 2.448 kg/m · 1.645 lb/ft |
| 30 mm | 1.008 kg/m · 0.677 lb/ft | 1.312 kg/m · 0.882 lb/ft | 1.872 kg/m · 1.258 lb/ft | 2.368 kg/m · 1.591 lb/ft | 2.800 kg/m · 1.882 lb/ft | 3.168 kg/m · 2.129 lb/ft |
| 40 mm | 1.368 kg/m · 0.919 lb/ft | 1.792 kg/m · 1.204 lb/ft | 2.592 kg/m · 1.742 lb/ft | 3.328 kg/m · 2.236 lb/ft | 4.000 kg/m · 2.688 lb/ft | 4.608 kg/m · 3.096 lb/ft |
| 50 mm | 1.728 kg/m · 1.161 lb/ft | 2.272 kg/m · 1.527 lb/ft | 3.312 kg/m · 2.226 lb/ft | 4.288 kg/m · 2.881 lb/ft | 5.200 kg/m · 3.494 lb/ft | 6.048 kg/m · 4.064 lb/ft |
| 60 mm | 2.088 kg/m · 1.403 lb/ft | 2.752 kg/m · 1.849 lb/ft | 4.032 kg/m · 2.709 lb/ft | 5.248 kg/m · 3.526 lb/ft | 6.400 kg/m · 4.301 lb/ft | 7.488 kg/m · 5.032 lb/ft |
| 80 mm | 2.808 kg/m · 1.887 lb/ft | 3.712 kg/m · 2.494 lb/ft | 5.472 kg/m · 3.677 lb/ft | 7.168 kg/m · 4.817 lb/ft | 8.800 kg/m · 5.913 lb/ft | 10.368 kg/m · 6.967 lb/ft |
| 100 mm | 3.528 kg/m · 2.371 lb/ft | 4.672 kg/m · 3.139 lb/ft | 6.912 kg/m · 4.645 lb/ft | 9.088 kg/m · 6.107 lb/ft | 11.200 kg/m · 7.526 lb/ft | 13.248 kg/m · 8.902 lb/ft |
| 120 mm | 4.248 kg/m · 2.855 lb/ft | 5.632 kg/m · 3.785 lb/ft | 8.352 kg/m · 5.612 lb/ft | 11.008 kg/m · 7.397 lb/ft | 13.600 kg/m · 9.139 lb/ft | 16.128 kg/m · 10.838 lb/ft |
| 150 mm | 5.328 kg/m · 3.580 lb/ft | 7.072 kg/m · 4.752 lb/ft | 10.512 kg/m · 7.064 lb/ft | 13.888 kg/m · 9.332 lb/ft | 17.200 kg/m · 11.558 lb/ft | 20.448 kg/m · 13.740 lb/ft |
| 200 mm | 7.128 kg/m · 4.790 lb/ft | 9.472 kg/m · 6.365 lb/ft | 14.112 kg/m · 9.483 lb/ft | 18.688 kg/m · 12.558 lb/ft | 23.200 kg/m · 15.590 lb/ft | 27.648 kg/m · 18.579 lb/ft |
Rows: depth (mm). Columns: wall thickness (mm). Computed for Stainless Steel 316 at 8000 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. Stainless Steel 316 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 stainless steel 316
Identical density to 304, so weight tables can be shared between them — but not material selection. The 2–3 % molybdenum addition is what buys resistance to chlorides and to the sulphuric and acetic acid environments that pit 304. For a weight take-off the two are interchangeable; for a coastal or process-chemical application they are not, and the substitution is usually made for the wrong reason (availability) without recalculating corrosion allowance.
- Density
- 8,000 kg/m³ = 0.2890 lb/in³ · 1.0191× carbon steel · typical spread ±1 %
- Specification
- ASTM A240 / A276 (UNS S31600)
- Equivalents
- EN 1.4401 · JIS SUS316 · GB 06Cr17Ni12Mo2
- Typical uses
- Marine and coastal hardware · Pharmaceutical and dairy process plant · Chemical storage and pipework · Pulp and paper
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
SS 316 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 stainless steel 316 rectangular tube weigh?
At the reference dimensions (a = 60 mm, b = 40 mm, t = 3 mm) a stainless steel 316 rectangular tube of this size weighs 4.512 kg/m, or 3.032 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 stainless steel 316's density of 8,000 kg/m³ gives 4.512 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 stainless steel 316 weigh more or less than steel?
It is heavier than carbon steel for the same section — about 2 % heavier at 8,000 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 1.0191× 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 ss 316 rectangular tube weigh the same as a ss 316 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 SS 316 weight or carbon steel weight for costing?
Use the material you are actually buying. At 8,000 kg/m³ against carbon steel's 7,850 kg/m³, the same rectangular tube differs by 1.9 % 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
- 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 SS 316 sections
The same density applied to every shape the site covers.
- SS 316 round bar — A = π/4 · d²
- SS 316 square bar — A = a²
- SS 316 hexagonal bar — A = (√3/2) · AF² ≈ 0.8660 · AF²
- SS 316 flat bar — A = w · t
- SS 316 plate — A = w · t
- SS 316 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 8,000 kg/m³ (ASTM A240 / A276 (UNS S31600)). 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.