Pipe weight calculator: cylinder, bar and tube weight
This pipe weight calculator finds the weight of any cylinder by multiplying its volume by the density of the material: mass = π × r² × L × ρ for a solid bar, and π × (R² − r²) × L × ρ for a pipe or tube. A carbon steel bar 2 in across and 36 in long weighs about 32.07 lb (14.55 kg).
Contents
Weight = volume × density. A steel bar with d = 2 in and L = 36 in: V = π × 1² × 36 = 113.10 in³ = 0.0018533 m³; × 7,850 kg/m³ = 14.55 kg = 32.07 lb.
The calculator above handles solid rods and bars as well as tubes and pipes (outside diameter and wall thickness), in inches, feet, millimeters or meters, for the materials listed below or any density you enter. The volume step uses the standard cylinder volume calculator formula; only the multiplication by density is added.
The weight formula for a cylinder
Weight is volume times density. The density, written ρ, is the mass of one unit of volume of the material: 7,850 kg per cubic meter for typical carbon steel, 1,000 kg/m³ for water. Units must match: cubic meters with kg/m³, cubic feet with lb/ft³, cubic inches with lb/in³.
| Shape | Volume | Weight |
|---|---|---|
| Solid bar or rod, radius r | π × r² × L | ρ × π × r² × L |
| Tube, outer radius R, inner radius r | π × (R² − r²) × L | ρ × π × (R² − r²) × L |
| Pipe, outside diameter D, wall t | π × t × (D − t) × L | ρ × π × t × (D − t) × L |
The last line is the tube formula rewritten for the way pipe is measured. With R = D ÷ 2 and r = R − t, R² − r² = t × (D − t). It avoids computing the inside diameter. The page on hollow cylinder volume shows the same identity with more examples.
Weight per foot and per meter for carbon steel
Putting the density of steel, 7,850 kg/m³, into the formulas gives quick factors. They are rounded to four figures and assume that density exactly.
- Steel pipe, inches: lb per foot = 10.69 × (D − t) × t.
- Steel pipe, millimeters: kg per meter = 0.02466 × (D − t) × t.
- Steel round bar, inches: lb per foot = 2.673 × d².
- Steel round bar, millimeters: kg per meter = 0.006165 × d².
For another material, multiply the steel result by the ratio of densities. Aluminum at 2,700 kg/m³ is 2,700 ÷ 7,850 = 0.344 times as heavy as steel of the same size.
Densities used by the calculator
These are typical values. Real alloys, grades and mixes vary by a few percent, so use the density from the material's data sheet when accuracy matters, through the custom density field. The lb/ft³ column is kg/m³ × 0.062428.
| Material | kg/m³ | g/cm³ | lb/ft³ | lb/in³ |
|---|---|---|---|---|
| Carbon steel | 7,850 | 7.85 | 490.1 | 0.2836 |
| Stainless steel (304) | 8,000 | 8.00 | 499.4 | 0.2890 |
| Aluminum | 2,700 | 2.70 | 168.6 | 0.0975 |
| Copper | 8,960 | 8.96 | 559.4 | 0.3237 |
| Brass | 8,500 | 8.50 | 530.6 | 0.3071 |
| Cast iron | 7,200 | 7.20 | 449.5 | 0.2601 |
| Lead | 11,340 | 11.34 | 707.9 | 0.4097 |
| Concrete (normal weight) | 2,400 | 2.40 | 149.8 | 0.0867 |
| Water | 1,000 | 1.00 | 62.4 | 0.0361 |
| PVC (rigid) | 1,380 | 1.38 | 86.2 | 0.0499 |
Worked examples
Steel round bar, in inches
A carbon steel bar is 2 in in diameter and 36 in long. The radius is 1 in, so V = π × 1² × 36 = 113.10 in³. Multiply by 0.2836 lb/in³: 32.07 lb. In metric, 113.10 in³ = 0.0018533 m³, and 0.0018533 × 7,850 = 14.55 kg. The shortcut agrees: 2.673 × 2² = 10.69 lb per foot, times 3 ft = 32.07 lb.
Steel pipe, weight per foot
A steel pipe measures 4.5 in outside with a 0.25 in wall. The wall cross-section is π × 0.25 × (4.5 − 0.25) = 3.338 in². Per foot: 3.338 × 12 × 0.2836 = 11.36 lb/ft, and the shortcut gives 10.69 × 4.25 × 0.25 = 11.36 lb/ft. A 20 ft length weighs about 227.2 lb. Published pipe tables can differ slightly from this, because they use their own density and nominal dimensions.
Aluminum tube, in millimeters
An aluminum tube is 50 mm outside with a 3 mm wall and is 6 m long. R = 25 mm and r = 22 mm, so the cross-section is π × (25² − 22²) = π × 141 = 442.96 mm². The volume is 442.96 × 6,000 = 2,657,787 mm³ = 0.0026578 m³. Multiply by 2,700 kg/m³: 7.18 kg, or 15.82 lb. That is 1.196 kg per meter.
Copper tube, in millimeters
A copper tube measured at 22 mm across with a 1 mm wall weighs π × 1 × (22 − 1) × 1,000 mm³ per meter × 8,960 kg/m³ = 0.591 kg per meter, so a 3 m length weighs 1.77 kg.
A cylinder of water, in pounds
A container 12 in across holds water 24 in deep. V = π × 6² × 24 = 2,714.3 in³, which is 11.75 US gallons or 1.5708 ft³. At 62.43 lb/ft³, the water weighs 98.1 lb (44.48 kg). Gallons times 8.345 lb gives the same answer; the cylinder volume in gallons page explains the conversion from cubic inches.
A concrete column
A round column 12 in across and 8 ft tall contains π × 0.5² × 8 = 6.283 ft³ of concrete. At 149.8 lb/ft³ it weighs about 941 lb (427 kg). To size the pour in cubic feet and cubic yards first, see cubic feet of a cylinder.
Weight per unit length table: carbon steel round bar
Computed from 7,850 kg/m³ and full-precision π, then rounded.
| Diameter | lb per foot | Diameter | kg per meter |
|---|---|---|---|
| 0.5 in | 0.668 | 10 mm | 0.617 |
| 0.75 in | 1.503 | 16 mm | 1.578 |
| 1 in | 2.673 | 20 mm | 2.466 |
| 1.5 in | 6.014 | 25 mm | 3.853 |
| 2 in | 10.69 | 32 mm | 6.313 |
| 3 in | 24.06 | 50 mm | 15.41 |
| 4 in | 42.77 | 100 mm | 61.65 |
Common mistakes
- Mixing units. A volume in cubic inches times a density in kg/m³ gives a meaningless number. Convert the volume, or use the density in lb/in³.
- Using the outside diameter for a pipe as if it were solid. A pipe's weight comes from its wall only; subtract the bore.
- Diameter in place of radius. In π × r² the radius is squared; using the diameter gives four times the weight.
- Forgetting the contents. A full pipe or tank weighs the metal plus the liquid. Compute both and add them; for the liquid, use the inside diameter.
- Treating the result as exact. Densities vary with alloy and mix, and real stock has dimensional tolerances. The result is an estimate.
For volume in metric units before weighing, the cylinder volume in liters page converts mm, cm and m. One liter of water is about 1 kg.
FAQ
How do you find the mass of a cylinder?
Multiply its volume by the density of the material: m = ρ × π × r² × h. Work in meters and kg/m³ to get kilograms, or in feet and lb/ft³ to get pounds. A steel bar 2 in across and 36 in long has a volume of 113.10 in³ and weighs about 32.07 lb at 7,850 kg/m³.
How do you calculate the weight of a pipe?
Find the volume of the wall only, π × t × (D − t) × L, where D is the outside diameter and t the wall thickness, then multiply by the density. For carbon steel at 7,850 kg/m³ this becomes lb per foot = 10.69 × (D − t) × t with D and t in inches.
What is the formula for the weight of a steel round bar?
With the diameter d in inches, a carbon steel bar at 7,850 kg/m³ weighs 2.673 × d² pounds per foot. With d in millimeters, it weighs 0.006165 × d² kilograms per meter.
How much does a cylinder of water weigh?
Water weighs about 62.43 lb per cubic foot, or 8.345 lb per US gallon (1 kg per liter). A cylinder 12 in across and 24 in tall holds 11.75 gallons of water, about 98.1 lb.
How do I convert kg/m³ to lb/ft³?
Multiply by 0.062428. Steel at 7,850 kg/m³ is about 490.1 lb/ft³; water at 1,000 kg/m³ is 62.43 lb/ft³.
Can I use this for square tube?
Not directly: the calculator is for round sections. For a square tube of width W and wall t, the cross-section is W² − (W − 2t)²; multiply it by the length and the density. Rounded corners make the real tube slightly lighter.
Related
- Hollow cylinderThe volume of a hollow cylinder is V = π(R² − r²)h. Find the material in a tube or pipe wall from radii, diameters or wall thickness, with worked examples.
- Cubic feetCubic feet of a cylinder = π × r² × h with r and h in feet. Mixed feet and inches, cubic inches ÷ 1,728, cubic yards and gallons, with a table per foot.
- Cylinder volume in gallonsFind the volume of a cylinder in gallons: π × r² × h in inches ÷ 231, or in feet × 7.48052. US and imperial gallons, worked examples and a capacity chart.
Updated October 12, 2026