How do I calculate the weight of a rectangular tube?

Multiply the cross-sectional area of the metal by the length and material density. Cross-sectional area = (W × H) − ((W − 2t) × (H − 2t)), where W is outer width, H is outer height, and t is wall thickness. Then: Weight = Cross-sectional area × Length × Density. For example, a 50×25×2 mm mild steel tube has a cross-section of 284 mm² and weighs 2.23 kg per meter.

What is the density of mild steel for rectangular tube weight calculation?

Mild steel (MS) has a density of 7,850 kg/m³ (0.2836 lb/in³). This is the standard value used for all carbon steel grades including IS 2062 and ASTM A500 Grade B. Carbon steel and galvanized iron (GI) use the same base density of 7,850 kg/m³, though GI tubes are 3–6% heavier in practice due to the zinc coating.

How much does a 50×25×2mm MS rectangular tube weigh per meter?

A 50×25×2mm mild steel rectangular tube weighs approximately 2.23 kg per meter. Here's the calculation: Cross-sectional area = (50×25) − (46×21) = 1,250 − 966 = 284 mm². Weight per meter = 284 × 10⁻⁶ × 7,850 = 2.23 kg/m. A standard 6-meter length weighs 13.38 kg, and weight per foot is approximately 1.50 lb/ft.

How do I calculate aluminum rectangular tube weight?

Use the same formula with aluminum density: 2,710 kg/m³ for Aluminum 6061 or 2,690 kg/m³ for Aluminum 6063. Aluminum tubes weigh about 65% less than steel tubes of the same dimensions. For example, a 50×25×2mm aluminum 6061 tube weighs 284 × 10⁻⁶ × 2,710 = 0.77 kg/m, compared to 2.23 kg/m for mild steel.

How do I calculate SS rectangular tube weight?

Stainless steel (SS) rectangular tubes use density 8,000 kg/m³ for both SS 304 and SS 316 grades — about 2% heavier than mild steel. The formula is identical: Weight = (W×H − (W−2t)×(H−2t)) × L × 8,000 × 10⁻⁶. For a 50×25×2mm SS 304 tube, the weight per meter is 284 × 10⁻⁶ × 8,000 = 2.27 kg/m (vs 2.23 kg/m for mild steel).

Can I calculate the weight of a rectangular tube in pounds?

Yes. Toggle the unit selector to Imperial (in) and enter dimensions in inches with length in feet. The calculator shows weight in pounds (lb) using the same formula with appropriate unit conversions. You can also see both kg and lb values simultaneously in the results. To convert manually: 1 kg = 2.20462 lb, or use weight per foot (lb/ft) for quick reference.

Rectangular Tube Weight Calculator

Units

Material

Common RHS sizes

Outer Width (mm)

Outer Height (mm)

Wall Thickness (mm)

Tube Length (m)

Quantity

Water weight inside tube

Includes the weight of water filling the hollow section.

Cost estimate

Use price per kg for the selected units.

Rectangular Tube · Mild Steel (MS)

6 m each

Total tube weight

13.38kg

29.49 lb

Weight Breakdown

Linear weight, dimensions, and material details

Weight per meter

2.229kg/m

1.498 lb/ft

Weight per foot

1.498lb/ft

2.229 kg/m

Cross-section area

284 mm²

0.4402 in²

Inner dimensions

46 × 21 mm

Material volume per meter

284 cm³/m

Formula Used

The exact formula applied for rectangular tube weight

Rectangular tube

Weight (kg) = (W×H − (W−2t)×(H−2t)) × 10⁻⁶ × L × ρ × Q

W = outer width, H = outer height, t = wall thickness (all mm) · L = length (m) · ρ = density (kg/m³) · Q = quantity

Density (ρ) = 7850 kg/m³ (Mild Steel (MS))

What Is a Rectangular Tube Weight Calculator?

Calculate RHS tube weight in kg/m, lb/ft, and total weight for any material

A rectangular tube weight calculator estimates the theoretical weight of rectangular hollow sections (RHS) from outer width, outer height, wall thickness, length, and material density — using the standard sharp-corner geometric formula. It is used by structural engineers, fabricators, steel traders, and procurement teams for material ordering, load calculations, freight estimation, and cost planning.

materials

MS, SS, GI, Aluminum, Copper, Brass…

Dual

units

Metric (mm/kg) & Imperial (in/lb)

RHS

only

Purpose-built for rectangular tubes

Rectangular hollow sections (RHS), also called rectangular tubes or box sections, are widely used in construction, infrastructure, automotive frames, material handling, and architectural applications. Unlike generic pipe calculators that force a shape selection, this tool is purpose-built for rectangular tubes — no extra clicks, no irrelevant fields.

How to Calculate Rectangular Tube Weight

A four-step process from dimensions to total weight

Select Material

Choose from 9 presets — Mild Steel (MS), Stainless Steel 304/316, Galvanized Iron (GI), Carbon Steel, Aluminum 6061/6063, Copper, and Brass. Each has a pre-loaded density. Use Custom Density for unlisted alloys.

Enter Dimensions

Input the outer width, outer height, and wall thickness. All dimensions use the selected unit system (mm or inches). The wall thickness must be less than half the smaller of width or height.

Set Length & Quantity

Enter the tube length (typically 6 m or 20 ft) and quantity. Use the +/- stepper for batch calculations. Enable water weight or cost estimate if needed.

Read the Results

Get total weight in kg and lb, weight per meter (kg/m), weight per foot (lb/ft), cross-section area, inner dimensions, material volume, and optional water weight and cost.

Core Formula

Weight (kg) = (W×H − (W−2t)×(H−2t)) × 10⁻⁶ × L × ρ × Q

Where W = outer width, H = outer height, t = wall thickness (all in mm), L = length in meters, ρ = material density in kg/m³, Q = quantity. The 10⁻⁶ factor converts mm² to m² for dimensional consistency with kg/m³.

Worked Example: 50×25×2 mm MS Tube

For a mild steel tube (ρ = 7,850 kg/m³) at 6 meters length:

Cross-section = 50×25 − (50−4)×(25−4) = 1,250 − 966 = 284 mm²
Weight per meter = 284 × 10⁻⁶ × 7,850 = 2.23 kg/m
Total weight = 2.23 × 6 = 13.38 kg
Weight per foot = 1.50 lb/ft

Common Rectangular Tube Weights at a Glance

Quick reference for frequently used RHS sizes and materials

50×25×2 mm MS Tube

13.38 kg

2.23 kg/m · 1.50 lb/ft

Width 50 · Height 25 · Wall 2 mm · 6 m

Mild Steel (7,850 kg/m³)

80×40×3 mm SS 304 Tube

32.83 kg

5.47 kg/m · 3.68 lb/ft

Width 80 · Height 40 · Wall 3 mm · 6 m

Stainless Steel 304 (8,000 kg/m³)

100×50×4 mm GI Tube

53.51 kg

8.92 kg/m · 5.99 lb/ft

Width 100 · Height 50 · Wall 4 mm · 6 m

Galvanized Iron (7,850 kg/m³)

50×25×2 mm Aluminum Tube

4.62 kg

0.77 kg/m · 0.52 lb/ft

Width 50 · Height 25 · Wall 2 mm · 6 m

Aluminum 6061 (2,710 kg/m³)

Material Density Reference

Standard densities used in rectangular tube weight calculations

Material	kg/m³	lb/in³
Mild Steel (MS)	7,850	0.2836
Carbon Steel (CS)	7,850	0.2836
Stainless Steel 304	8,000	0.2890
Stainless Steel 316	8,000	0.2890
Galvanized Iron (GI)	7,850	0.2836
Aluminum 6061	2,710	0.0979
Aluminum 6063	2,690	0.0972
Copper	8,940	0.3230
Brass	8,500	0.3070

Densities shown are typical reference values. Actual density may vary slightly by grade and manufacturing process. Use the Custom Density option for non-standard alloys.

Tips for Accurate Rectangular Tube Weight

Practical advice for procurement, fabrication, and structural planning

Use metric for Indian standard sizes

IS 4923 and IS 1161 RHS tubes are specified in mm. Stick to metric for accurate matching with supplier catalogs and IS standard weight charts.

Account for coating weight

Galvanized (GI) tubes are 3–6% heavier than bare MS due to zinc coating. The calculator shows base steel weight — add 5% for GI estimates.

Verify with supplier weight charts

Manufacturing tolerances per IS 4923 allow ±8% on wall thickness. For critical projects, cross-check calculated weight against the supplier's actual weight certificate.

Add 3–5% for weld and end finishing

Fabrication adds weight through weld metal, end plates, and brackets. Factor this in when estimating total structural weight.

Common Mistakes When Calculating Tube Weight

Avoid these frequent errors that lead to wrong weight estimates

Using outer dimensions as inner

The hollow area is (W−2t)×(H−2t), not W×H. Forgetting to subtract twice the wall thickness from each side overestimates weight significantly.

Confusing RHS with solid bar weight

A 50×25 mm solid MS bar weighs 9.81 kg/m. The equivalent RHS tube with 2mm wall weighs only 2.23 kg/m — a 77% difference.

Ignoring corner radius

Real RHS tubes have rounded external corners (radius ≈ 2–3× wall thickness). The sharp-corner formula gives weight about 1–2% higher than actual. This is usually within safety margin.

Mixing unit systems

The calculator always uses kg/m³ for density regardless of the selected unit system. The custom density field expects kg/m³ even in imperial mode.

Frequently Asked Questions

Common questions about rectangular tube weight calculation

The formula is: W = (W_outer × H_outer − (W_outer − 2t) × (H_outer − 2t)) × 10⁻⁶ × L × ρ, where W_outer = outer width (mm), H_outer = outer height (mm), t = wall thickness (mm), L = length (m), ρ = material density (kg/m³). The 10⁻⁶ factor converts mm² to m². The result gives weight in kg. For imperial units, enter dimensions in inches — the calculator handles all unit conversions internally and always uses kg/m³ for density.

For mild steel (MS) rectangular tubes, use density of 7,850 kg/m³. First calculate cross-sectional area in mm²: Area = (Width × Height) − ((Width − 2 × thickness) × (Height − 2 × thickness)). Then weight per meter = Area × 0.000001 × 7,850 kg. For example, a 50×25×2mm MS tube weighs [(50×25) − (46×21)] × 0.00785 = 284 × 0.00785 = 2.23 kg/m. A standard 6m length weighs about 13.38 kg.

Rectangular tube and Rectangular Hollow Section (RHS) refer to the same product — a hollow structural section with a rectangular cross-section. 'RHS' is the standard technical term used in structural engineering and steel manufacturing (per EN 10219 and ASTM A500 standards). 'Rectangular tube' is the more common term used in general construction and online searches. They are interchangeable in the weight formula.

Wall thickness has a nearly linear effect on weight — doubling the wall thickness roughly doubles the weight. This is because the cross-sectional area changes with the square of the wall thickness reduction from the outer rectangle. For example, increasing from 2mm to 3mm wall on a 50×25mm tube increases the cross-section from 284 mm² to 414 mm² (46% more area and weight). The calculator shows real-time weight changes as you adjust thickness.

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Last updated May 15, 2026