Cylinder Volume Calculator
Diameter × height → volume in six units. For columns, tanks, drums, pipes.
How to use
Enter the diameter (or radius) and height. The calculator returns the volume in six common units, including cubic yards for concrete and US barrels for fuel storage.
- Pick the input unit (feet, inches, metres, centimetres).
- Choose whether you have the diameter (across the circle) or radius (centre to edge). Most rebar callouts and pipe specs give diameter.
- Enter the cylinder height in the same unit.
- Read volume in cubic feet, cubic metres, US gallons, litres, cubic yards (concrete), and US barrels.
Reviewed 6 June 2026 · methodology cited
About this calculator
A cylinder is one of the most common shapes in construction. Concrete piers and Sonotubes for deck footings, structural columns, water-storage tanks, propane and heating-oil tanks, drainage pipes, well casings, grain silos, and even the volume inside a kitchen pot — all are cylinders. The volume formula is unchanged across all of these uses; what differs is the unit you express the answer in.
This calculator handles diameter or radius (you can flip between them), takes input in feet, inches, metres, or centimetres, and returns the volume in six units chosen for North American practice: cubic feet (general), cubic metres (SI / Canadian engineering), US gallons (liquid capacity), litres (metric capacity), cubic yards (the way concrete is sold in the US and Canada), and US barrels (the way oil and fuel are tracked).
The math behind it
Volume of a cylinder = π × r² × h, where r is the radius (half the diameter) and h is the height. With diameter d, the equivalent formula is V = π × (d/2)² × h = π × d² × h ÷ 4.
Worked example — a 12-inch-diameter Sonotube footing 4 feet tall: r = 6 in = 0.5 ft, h = 4 ft, V = π × 0.5² × 4 = π × 0.25 × 4 = π ≈ 3.14 ft³. That's the volume of concrete in one footing. For a deck with eight footings, you need 8 × 3.14 = 25.1 ft³, which is 25.1 ÷ 27 = 0.93 cubic yards — round up to 1 yard when ordering.
Unit conversions: 1 ft³ = 0.02832 m³ = 7.481 US gal = 28.32 L = 1/27 yd³ = 0.178 US barrels. Cubic yards are the way ready-mix concrete is sold in North America; 1 US barrel = 42 gallons (the petroleum barrel, different from a US beer barrel).
Common cylinder applications
| Application | Typical size | Volume at typical size |
|---|---|---|
| 8″ Sonotube footing × 4′ deep | 8 in × 4 ft | 1.40 ft³ = 0.052 yd³ = 10.4 US gal |
| 10″ Sonotube footing × 4′ deep | 10 in × 4 ft | 2.18 ft³ = 0.081 yd³ = 16.3 US gal |
| 12″ Sonotube footing × 4′ deep | 12 in × 4 ft | 3.14 ft³ = 0.116 yd³ = 23.5 US gal |
| 16″ concrete pier × 8′ deep | 16 in × 8 ft | 11.2 ft³ = 0.413 yd³ = 83.4 US gal |
| Standard 55-gal drum | 23 in × 35 in | 7.30 ft³ = 54.6 US gal (full) |
| Residential 250-gal heating-oil tank | 27 in × 5 ft | 19.9 ft³ = 149 US gal usable |
| 500-gal propane tank (horizontal) | 37 in × 9.5 ft | 70.9 ft³ = 530 US gal · 400 gal usable @ 80 % |
| 1,000-gal propane tank | 41 in × 16 ft | 147 ft³ = 1,100 US gal · 800 gal usable @ 80 % |
| Standard 4″ PVC drain (10′ length) | 4 in × 10 ft | 0.87 ft³ = 6.5 US gal water |
| Standard 6″ well casing (50′) | 6 in × 50 ft | 9.82 ft³ = 73.4 US gal |
Concrete, tanks, and pipes
For concrete, always round UP when ordering ready-mix. Sonotube and pier estimates tend to be tight; spillage, over-excavation, and form imperfection mean you usually want 5–10 percent extra. A 0.93-yard order becomes a 1-yard order; a 2.8-yard order becomes a 3-yard order. Ready-mix trucks have a 10-yard practical maximum per load — for larger jobs you'll need multiple loads or a pump truck, both worth confirming with your supplier before you place the formwork.
For tanks, the volume calculation gives total internal capacity. Usable capacity is always less: water tanks have a fill line and an air gap; propane and natural-gas tanks have a 20-percent safety vapour space (so a 1,000-gallon propane tank holds 800 gallons of liquid); fuel-oil tanks usually leave 5–10 percent for thermal expansion. Always check the tank specification sheet for usable versus nominal capacity.
For pipe capacity (water in a horizontal main, for example), the volume calculation gives the static water-content of one length. Flow capacity is a different problem — it depends on velocity, pressure, and friction loss, not just cross-section. Use the calculator for filling/flushing/draining estimates, not for sizing supply or drainage.
Frequently asked questions
How do I calculate the volume of a cylinder?
Volume = π × radius² × height. If you only have the diameter, the radius is half of it. So for a 12-inch-diameter, 4-foot-tall cylinder: radius = 6 in = 0.5 ft, volume = π × 0.5² × 4 = 3.14 cubic feet. The same formula works in any unit — just use the same unit for radius and height, and the result will be in cubic units of that base.
How much concrete is in one Sonotube footing?
For an 8-inch-diameter Sonotube 4 feet deep, about 1.4 cubic feet, which is 0.052 cubic yards. A 10-inch by 4-foot footing is 2.18 cubic feet (0.081 yd³). A 12-inch by 4-foot footing is 3.14 cubic feet (0.116 yd³). For a deck with 8 footings at 12 inches × 4 feet, you need 8 × 0.116 = 0.93 cubic yards — round up to 1 yard when ordering ready-mix.
How many gallons does a cylindrical tank hold?
Multiply π × radius² × height to get cubic feet, then multiply by 7.481 for US gallons. So a 4-foot-diameter water tank that's 6 feet tall: r = 2 ft, V = π × 4 × 6 = 75.4 ft³ = 564 US gallons. Note that propane tanks have a 20-percent vapour space, so a 564-gallon tank only safely holds 451 gallons of liquid.
What is the difference between a cubic yard and a cubic foot?
A cubic yard is the volume of a cube one yard (3 feet) on each side, so 3 × 3 × 3 = 27 cubic feet. Ready-mix concrete is sold by the cubic yard in North America. To convert: cubic yards = cubic feet ÷ 27. So 54 ft³ = 2 yd³; 25 ft³ = 0.93 yd³ (which you would order as 1 yard, since concrete is sold in whole or half-yard increments).
Is a US oil barrel the same as other barrels?
No. The US oil barrel is 42 US gallons (158.987 litres) — used for crude oil and most petroleum products. A US beer barrel is 31 US gallons. An imperial dry barrel is 36 imperial gallons. The cubic-feet to barrels conversion this calculator uses is 1 ft³ ≈ 0.178 oil barrels, the petroleum standard.
Can I use this for non-circular cylinders (oval, hexagonal)?
No. This calculator assumes a circular cross-section. For oval tanks, hexagonal columns, or other prismatic shapes, calculate the cross-sectional area separately (length × width for rectangular, π × a × b for elliptical, more complex for hex) then multiply by the height.