For a solid cylinder:

Use diameter by substituting r=d/2.

Choose solid or hollow geometry, enter dimensions and mass or material density, then solve the desired quantity. Use consistent dimensional units or let the tool convert them before volume is calculated.

For a known material density, mass is m=ρV. Steel, aluminum and other metal-cylinder weight calculations are therefore geometry problems plus the correct material density.

For a tube or hollow cylinder, subtract inner volume from outer volume:

Ignoring the inner void is one of the easiest ways to overestimate tube mass by a spectacular amount.

If mass, density and two geometric quantities are known, the cylinder equations can be rearranged to solve the missing dimension. This is useful for checking stock sizes and rough design targets.

Once geometric volume is known, convert it to litres, US gallons, cubic inches or cubic feet. A volume conversion does not require density; density is needed only when converting that volume to mass or weight.

Steel density varies modestly with composition, but a common engineering estimate for carbon steel is about 7850 kg/m³. Stainless grades and specialty alloys differ, so use the grade-specific value when accuracy matters.

Machined cylinders can have chamfers, holes, threads, end caps or taper. A perfect-cylinder formula describes ideal geometry. For close mass estimates, use finished-part CAD volume or subtract secondary features.

A solid steel cylinder 50 mm in diameter and 200 mm long has volume about 0.0003927 m³. At 7850 kg/m³, estimated mass is about 3.08 kg. A hollow tube with the same outer dimensions can weigh far less because inner volume is removed.

Volume can be reported in m³, cm³, litres, in³, ft³ or gallons. Mass can be converted independently. The calculation sequence is geometry first, material density second, then output conversion.

Diameter is not radius, inner diameter must be smaller than outer diameter, and hollow tubes require subtracting inner volume. End caps, flanges and fittings are additional geometry and should not be silently assumed into a plain-cylinder model.

Metal rods, tubes and shafts are often estimated from standard densities: aluminum around 2700 kg/m³, carbon steel around 7850 kg/m³, copper around 8960 kg/m³ and titanium around 4500 kg/m³. Actual alloy values should be checked for procurement, lifting or precision mass work.

For a hollow tube, material occupies the annular cross-section rather than the full outer circle. As wall thickness becomes small relative to diameter, using the solid-cylinder formula can overestimate mass dramatically. The calculator therefore keeps outer and inner diameter explicit instead of hiding wall geometry behind a single “tube weight” shortcut.

Common uses include estimating rods, pipes, rollers, tanks, shafts, cores and laboratory samples. Pressure vessels, cylinders with domed ends and tapered parts need more detailed geometry than this ideal straight-cylinder model.