Calculate the volume of a cylinder in cubic feet. Enter radius or diameter and height in inches, feet, cm, or meters. Instantly see volume in ft³, gallons, and liters plus surface area breakdown.
The Cubic Feet of a Cylinder Calculator helps you quickly determine the volume of any cylindrical shape in cubic feet (ft³). Whether you are sizing a water tank, estimating material for a concrete column, measuring pipe capacity, or planning a cylindrical cistern, knowing the exact volume in cubic feet is essential for purchasing materials, estimating costs, and meeting building codes.
The formula is straightforward: V = πr²h, where r is the radius of the circular base and h is the height (or length) of the cylinder. This calculator takes care of all the unit conversions so you can enter measurements in inches, feet, centimeters, or meters and instantly receive the result in cubic feet. Alongside the primary volume output you also see the equivalent in US gallons and liters, making it easy to cross-reference with fluid capacity specifications.
Additionally, the tool computes the base area, lateral (side) surface area, and total surface area of the cylinder — valuable when estimating paint, insulation, or wrapping material. Eight common presets cover everyday scenarios such as 55-gallon drums, IBC totes, pipes, hot tubs, silos, and swimming pools, so you can compare your cylinder against well-known references. A conversion table rounds out the page for quick unit look-ups.
Use this calculator when the volume needs to end in cubic feet because that is how tanks, pipes, tubs, and storage spaces are often specified on plans and product sheets. It is especially useful for checking water capacity in vertical tanks, estimating the internal volume of ducting or pipe runs, and converting a cylinder into gallons or liters without manually switching units first.
Because the interface also shows base area, lateral area, and total surface area, it is practical for jobs where you need both capacity and coverage. That makes it useful for insulation estimates, paint or wrap calculations, and comparing common presets such as a 55-gallon drum, a hot tub, or a silo against your own dimensions.
V = π × r² × h, where r is the radius and h is the height, both converted to feet. For diameter input, r = d / 2. Surface area = 2πr² + 2πrh.
Result: 141.37 ft³
With radius mode selected, entering a radius of 3 feet and height of 5 feet gives V = π × 3² × 5 = π × 45 ≈ 141.37 ft³. The calculator also converts that to about 1,057.39 US gallons and 4,002.77 liters, while showing a base area of about 28.27 ft² and a total surface area of about 150.80 ft².
Cubic feet is one of the most practical volume units for building services, utility work, and storage planning. Water tanks, air chambers, drums, culverts, and round containers are often measured in feet even when the manufacturer gives diameter in inches. This calculator handles that mixed-unit reality by letting you enter radius or diameter in inches, feet, centimeters, or meters and still produce a clean ft³ result. That is much faster than converting everything by hand before you even start the cylinder formula.
Many real jobs need more than one answer from the same measurements. A tank installer may need cubic feet for structural space, gallons for water capacity, and liters for a spec sheet. A fabricator may also need the side surface area to estimate paint, insulation, or cladding. This calculator groups those outputs together, so one set of radius and height inputs gives you the cylinder volume, the circular base area, the lateral area, and the total surface area. The surface-area breakdown bars make it easier to see whether most of the exterior area is on the curved side or on the two circular ends.
For liquid capacity, always use the internal radius or internal diameter, not the outside wall dimension. Pipes, drums, and tanks can lose meaningful capacity if the wall thickness is ignored. If you measure diameter with a tape, switch the calculator to diameter mode so you do not introduce an extra divide-by-two step on paper. For horizontal pipes, enter the pipe length as the height because the cylinder formula does not depend on orientation. If you are comparing against manufacturer ratings, use the gallon and liter outputs as a quick sanity check before ordering or installation.
A standard 55-gallon drum holds approximately 7.35 cubic feet. The drum is roughly 23 inches in diameter and 33.5 inches tall.
Volume = π × r² × h. Ensure the radius (r) and height (h) are both in feet before multiplying. If you have the diameter, divide it by 2 to get the radius.
Multiply the cubic feet value by 7.48052 to get US liquid gallons.
Yes. The volume formula is the same regardless of orientation. Enter the pipe length as the "height" value.
The calculator uses the full-precision value of π and performs exact unit conversions, giving results accurate to multiple decimal places. Use this as a practical reminder before finalizing the result.
Divide the circumference by 2π to find the radius, then use that radius in this calculator. Radius = circumference / (2 × 3.14159).