Mass & density
How to Calculate Mass of a Cylinder
Volume is only half the story — add a material density to estimate the weight of a solid or filled cylinder in kg and pounds.
You cannot get weight from size alone, and this how to calculate mass of a cylinder is honest about that: pick a material or type in its density, and the tool combines it with the cylinder's volume to estimate the mass.
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 volume is worked out
The volume of a cylinder is:
V = π r² hA worked example
Worked example. Take a cylinder with a diameter of 10 cm (so a radius of 5 cm) and a height of 25 cm. The base area is π × 5² = 78.54 cm², and multiplying by the height gives a volume of about 1.96 litres (1,963 cm³ · 0.52 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.
How to work it out
- 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.
After you have your answer
Most jobs need one or two more things once the volume lands. The common follow-ups, with the numbers you need, are below:
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.
Where people go wrong
Two things trip people up: squaring the wrong number, and forgetting that the answer is cubic. If a result looks four times too big or too small, you have probably swapped radius and diameter somewhere, so it is always worth re-reading the measurement you are least sure of. It also helps to glance at the equivalent units; if the litre and gallon figures are both off by the same factor, the input is the culprit, not the maths.
Reading and converting your result
Because volume units are where most errors creep in, the tool does the converting for you. Enter your measurements once and every common unit appears together, from millilitres up to cubic metres and across to US and Imperial gallons. Pick whichever the task calls for and lift the rest from the list; nothing needs a second calculation. The result also updates live as you change a measurement, so you can compare two sizes quickly without starting over.
What to work out next
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:
When this comes in handy
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
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.
Good to know
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.