Mass & density
Density of Cylinder Calculator
Volume is only half the story — add a material density to estimate the weight of a solid or filled cylinder in kg and pounds.
Dimensions give you volume; weight needs one more thing — the density of whatever the cylinder is made of or filled with. This density of cylinder calculator multiplies volume by density (mass = ρ V) to estimate weight in kilograms and pounds.
Weight is where volume meets the real world. A tank's size tells you nothing about the load it puts on a floor until you bring in what is inside it, and the same round bar is feather-light in aluminium and heavy in steel. Density is the bridge between the two.
How the calculation works
- Measure across the circular end — the diameter or radius.
- If you measured the diameter, halve it to get the radius r.
- Square the radius and multiply by π to get the base area.
- Multiply the base area by the height h: V = π r² h.
- Convert the result into your preferred unit above.
Getting an accurate measurement
If you can only reach the top, measure the diameter across the opening and halve it. Keep every measurement in the same system, and let the tool convert between units for you.
The formula behind it
The volume of a cylinder is:
V = π r² hA worked example
Worked example. Take a cylinder with a diameter of 20 cm (so a radius of 10 cm) and a height of 40 cm. The base area is π × 10² = 314.16 cm², and multiplying by the height gives a volume of about 12.57 litres (12,566 cm³ · 3.32 US gallons).
Weight depends entirely on the material's density, which the tool needs as an input. Densities also vary with temperature and grade, so treat the mass as an estimate.
Conversions use standard factors: 1 US gallon = 231 in³, 1 Imperial gallon = 4.54609 L, 1 litre = 1000 cm³.
Follow-on questions, answered
To save you a second search, here are the related answers people most often want straight after this calculation:
Does temperature matter?
For liquids, slightly — density drifts a little with temperature. The presets use typical room-temperature values, which are close enough for almost all estimates.
What density should I use?
Pick a preset — water, steel, aluminium, concrete and more — or type a custom value. Density is what turns a volume into a weight, so the result depends directly on it.
What is the weight in pounds and kilograms?
Both are shown. The tool reports mass in kilograms, pounds and grams once you supply a density, so you can use whichever your job needs.
Common uses
A few of the jobs it gets used for:
- Estimating the shipping weight of round stock
- Sizing supports for a filled tank
- Comparing materials by weight for a part
Common mistakes to avoid
The commonest slip is using the diameter where the formula wants the radius, which on its own quadruples the base area. Close behind is mixing units, such as a radius in centimetres with a height in metres. Keep every length in the same unit, or let the tool convert, and double-check whether you measured to the centre or across the whole width. When a figure looks surprising, that width measurement is almost always where the problem is hiding, so re-read it first.
One result, every unit
One number, many units. Whatever you enter, the result lists the same volume as litres, US gallons, Imperial gallons, millilitres, cubic centimetres, cubic inches, cubic feet, cubic yards and cubic metres at the same time. You almost never have to convert by hand: read the figure in the unit your job uses and copy any of the others straight from the breakdown. If you need a shareable version, the copy-link button preserves your exact inputs so a colleague opens the page with the same calculation already filled in.
Keep going
Once you have your answer you may also want to work in cylinder volume solid rod & bar volume formula. These related calculators pick up where this one leaves off:
In short: measure the width and the height, keep them in the same unit, and the tool turns them into a volume you can read in litres, gallons, cubic feet or anything else, with the working shown so you can trust it. If a result ever looks off, re-enter the measurement you are least sure of, or switch to the diameter input and let the tool halve it for you, which catches the most common error before it matters.
Frequently asked questions
What is the formula for the volume of a cylinder?
V = π r² h — the area of the circular base (π r²) multiplied by the height (h). If you have the diameter instead of the radius, halve it first: r = d ÷ 2.Do I use radius or diameter?
What units can I use?
Is the volume of a cylinder squared or cubed?
Does this work for a tank or a pipe?
How do I calculate the mass of a cylinder?
mass = ρ × V. Water is about 997 kg/m³; steel is about 7850 kg/m³. Pick a material or enter a custom density above.