About

Miscalculating a cylinder's volume costs money. Overfill a concrete pour and you waste material. Underestimate a tank's capacity and you risk overflow or project delays. This calculator computes the exact volume of a right circular cylinder in cubic feet using the standard geometric formula V = π × r² × h, where r is the internal radius and h is the height (or length for horizontal cylinders). It accepts input in inches, feet, yards, centimeters, or meters and converts internally to feet before computation. Results are cross-converted to cubic yards, cubic meters, liters, and US gallons. Note: this tool assumes a perfect right circular cylinder. Real-world containers have wall thickness, weld seams, and dome heads that reduce usable volume by 2% to 5%. Always verify against manufacturer specs for critical applications.

Formulas

The volume of a right circular cylinder is computed from two measurements: the radius of the circular cross-section and the axial height.

V = π × r² × h

Where V is the volume, r is the radius of the base circle, h is the height (or length), and π ≈ 3.14159265. When the diameter d is given instead of radius, the formula becomes:

V = π × d²4 × h

To express the result in cubic feet, all linear dimensions must first be converted to feet. The conversion factors used are:

1 in = 112 ft 1 yd = 3 ft 1 cm = 0.032808 ft 1 m = 3.28084 ft

Output conversions applied to the cubic-feet result:

1 ft³ = 0.037037 yd³ 1 ft³ = 0.028317 m³ 1 ft³ = 1,728 in³ 1 ft³ = 28.3168 L 1 ft³ = 7.48052 gal

Reference Data

Object	Typical Diameter	Typical Height	Approx. Volume (ft³)	Approx. Volume (gal)
Soda Can	2.6 in	4.83 in	0.015	0.11
Paint Bucket (5 gal)	11.9 in	14.5 in	0.93	6.95
55-Gallon Drum	22.5 in	33.5 in	7.71	57.7
Residential Water Heater (40 gal)	18 in	46 in	6.78	50.7
Residential Water Heater (80 gal)	22 in	58 in	12.76	95.4
Propane Tank (20 lb)	12.5 in	18 in	1.28	9.6
Grain Silo (small farm)	14 ft	30 ft	4,618	34,541
Grain Silo (commercial)	30 ft	80 ft	56,549	422,988
Residential Well Casing (6 in)	6 in	100 ft	19.63	146.9
Concrete Column (12 in)	12 in	10 ft	7.85	58.7
Concrete Column (24 in)	24 in	12 ft	37.70	282.0
Above-Ground Pool (12 ft)	12 ft	4 ft	452.4	3,384
Above-Ground Pool (18 ft)	18 ft	4 ft	1,017.9	7,614
Above-Ground Pool (24 ft)	24 ft	4.5 ft	2,035.8	15,227
Oil Storage Tank (small)	10 ft	15 ft	1,178.1	8,813
Oil Storage Tank (large)	30 ft	40 ft	28,274	211,513
PVC Pipe (4 in × 10 ft)	4 in	10 ft	0.87	6.53
Concrete Pier (Sonotube 8 in)	8 in	4 ft	1.40	10.4
Cistern (Residential)	6 ft	8 ft	226.2	1,692
Industrial Smokestack	8 ft	100 ft	5,026.5	37,598

Frequently Asked Questions

Either works. Toggle the input mode between radius and diameter using the switch above the input field. When you enter diameter, the calculator internally divides by 2 to obtain the radius before applying V = πr²h. Most pipe and tank specs list outer diameter (OD). For internal volume, subtract twice the wall thickness from OD to get the inner diameter.

This calculator computes the geometric volume of a perfect cylinder. Real vessels have walls. A standard 55-gallon steel drum has a wall thickness of approximately 0.042 in (18-gauge). The difference between OD-based and ID-based volume for that drum is roughly 0.8%. For thick-wall concrete or cast iron pipes, the error can exceed 10%. Always use the internal diameter for capacity calculations.

Yes. The volume formula is orientation-independent. A horizontal cylinder has the same total volume as a vertical one with identical radius and length. However, if the tank is only partially filled, the fill-volume calculation for a horizontal cylinder requires a different formula involving the liquid depth and an inverse cosine function, which this calculator does not cover.

Manufacturers often quote nominal capacity (rounded), usable capacity (excluding headspace or dome volume), or water capacity at a specific temperature. A standard 55-gallon drum holds approximately 57.2 gal to the brim geometrically, but is rated at 55 gal to allow for expansion and safe handling. Always check whether the spec refers to brim-full, working, or nominal volume.

Concrete is sold by the cubic yard. Divide your cubic-feet result by 27 (since 1 yd³ = 27 ft³). This calculator displays cubic yards automatically in the results. For concrete orders, add 5% to 10% extra for waste, spillage, and form overrun.

Internally, all arithmetic uses IEEE 754 double-precision floating point (approximately 15 significant digits). The constant π is resolved to 3.141592653589793. Results are displayed rounded to 4 decimal places. For most construction and engineering tasks, 2 decimal places in cubic feet are sufficient.