A tube is a cylinder with a smaller cylinder removed from its center, so its cross-section is a ring. Pipes, sleeves, bushings, straws and rolled paper cores are all tubes. This calculator finds the volume of the wall material, the volume of the hollow inside, all of the surface areas and, if you pick a material, an estimated weight.
How to use the tube calculator
- Choose what you know under I know the: outer and inner diameters, outer diameter and wall thickness, inner diameter and wall thickness, or outer and inner radii.
- Enter those values and the Length (L).
- Pick the Units. Every dimension must use the same unit.
- Optionally choose a Material to get a weight in kilograms and pounds.
- Read the material volume (or weight) at the bottom of the tape, along with the diameters, wall thickness, cross-section area, hollow volume, capacity in liters and US gallons, outer volume, and the outer, inner, end and total surface areas.
Tube formulas
With outer radius R, inner radius r, wall thickness t = R − r and length L:
The weight is the material volume times the density: m = ρ × V. The calculator converts your volume to cubic meters and uses typical densities: 7,850 kg/m³ for carbon steel, 8,000 for stainless steel, 2,700 for aluminum, 8,960 for copper, 8,500 for brass, 1,400 for rigid PVC and 950 for HDPE.
Worked example: a 10-foot length of steel pipe
Nominal 2-inch Schedule 40 steel pipe has a published outside diameter of 2.375 in and a wall of 0.154 in.
Choose Outer diameter and wall thickness, enter D = 2.375, t = 0.154 and L = 120 (inches), and pick Carbon steel.
- Inner diameter: 2.375 − 2 × 0.154 = 2.067 in.
- Ring area: π(1.1875² − 1.0335²) ≈ 1.0745 in², so the steel volume is about 128.94 in³.
- Weight: about 16.59 kg (36.57 lb), or roughly 3.66 lb per foot, in line with published tables for this pipe.
- The bore holds 402.67 in³, about 1.74 US gallons of water.
Thinking about wall thickness
Weight grows with wall thickness
The ring area is the mean circumference times the thickness: π(R² − r²) = π(R + r)(R − r). For a fixed outside diameter, the weight therefore rises almost in step with the wall thickness, while the bore shrinks. A 110 mm PVC drain pipe with a 3.2 mm wall holds about 8.43 liters per meter and weighs about 1.5 kg per meter; its wall takes up only about 11% of the cross-section.
Inner and outer surfaces differ
Because the inside circle is smaller, the inner surface is always less than the outer one. On the steel pipe above, the outside measures about 895 in² over 10 feet and the inside about 779 in². Use the outer figure for paint or insulation and the inner figure for linings.
When to use a different tool
If the hole is negligible, such as a solid rod, use the cylinder calculator. For only the flat ring shape, such as a washer or gasket, use the annulus calculator. For tanks measured in gallons, the tank volume calculator handles horizontal and vertical tanks.
Common mistakes
- Entering a nominal pipe size instead of the true outside diameter.
- Using the full wall thickness when the diameter you entered was the inside diameter. Pick the matching option.
- Mixing millimeters and meters. Cubic units magnify the error: a factor of 1,000 in length is 1,000,000,000 in volume.
Frequently asked questions
How do I calculate the volume of material in a pipe?
Find the area of the ring-shaped cross-section, π(R² − r²), and multiply by the length. A tube with outer radius 3 cm, inner radius 2.5 cm and length 100 cm contains π × (9 − 6.25) × 100 ≈ 863.94 cm³ of material.
What is the difference between material volume and hollow volume?
Material volume is the solid wall of the tube, which sets its weight and cost. Hollow volume is the empty space inside, πr² × L, which sets how much liquid or air the tube holds.
How accurate is the weight?
The calculator multiplies the material volume by a typical density, such as 7,850 kg/m³ for carbon steel. Real alloys, plastics and manufacturing tolerances vary by a few percent, so treat the weight as an estimate and use the supplier's data for structural or shipping decisions.
Why does my pipe's nominal size not match the diameter I measured?
Pipe sizes such as 2-inch Schedule 40 are trade names. The actual outside diameter of 2-inch pipe is 2.375 inches, and the schedule sets the wall thickness. Always enter the measured or published outside diameter and wall, not the nominal size.
Does the total surface area include the inside of the tube?
Yes. The total adds the outer surface, the inner surface and the two ring-shaped ends. The outer and inner surfaces are also listed separately, since painting usually covers only the outside while coating or lining covers the inside.