Cylinder Volume in Gallons Calculator
Calculate the volume of a cylindrical tank, drum, pipe or pool in US liquid gallons. Enter the radius and height in inches or centimetres and get the capacity in gallons, litres and cubic feet.
Input unit
in
in
US liquid gallons — calculated from cubic inches ÷ 231
V = πr²h
5.88 gal- 1
Base area (πr²)
π × 6² = 113.0973 - 2
Volume in in³ (πr²h)
113.0973 × 12 = 1,357.168 - 3
Divide by 231 in³/gal
1,357.168 ÷ 231 = 5.8752
How does this calculator work?
Cylinder volume in US gallons = πr²h ÷ 231 (when r and h are in inches) or πr²h ÷ 3785.41 (when in centimetres). 1 US gallon = 231 in³ exactly = 3785.41 cm³. Use this for tanks, drums, pipes and pools.
Formula
How this is calculated
The volume of a cylinder is V = πr²h (cubic inches if the inputs are in inches, or cm³ if in centimetres). One US liquid gallon is defined as exactly 231 cubic inches, so the conversion is: gallons = πr²h ÷ 231 when working in inches. In metric, 1 US liquid gallon = 3785.411784 cm³, so gallons = πr²h ÷ 3785.411784.
This calculator is commonly used for sizing water storage tanks, stock tanks, fuel drums, pool volumes, and cylindrical pipes (where the "height" is the pipe length). For a tank only partially filled, scale the result by the fill fraction: gallons at 70% fill = full capacity × 0.70.
Note: this calculator uses US liquid gallons (231 in³). UK imperial gallons are slightly larger (277.42 in³ ≈ 4.546 L). For UK gallons, divide the cubic-inch volume by 277.42 instead.
Frequently asked questions
V = π × 6² × 12 ≈ 1357.17 in³. Dividing by 231 gives ≈ 5.87 US gallons. You can verify this in the calculator by entering r = 6, h = 12, unit = inches.
A US liquid gallon = 231 cubic inches ≈ 3.785 litres. A UK imperial gallon = 277.42 cubic inches ≈ 4.546 litres — about 20% larger. This calculator uses US liquid gallons only.
Yes — just enter the current liquid depth as the height instead of the full tank height. The calculator gives the volume of liquid in the cylinder up to that depth. For a full tank, enter the actual tank height.
Also known as
TG we-Calculate Editorial Team. (2026). Cylinder Volume in Gallons Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/cylinder-volume-gallons-calculator
TG we-Calculate Editorial Team. "Cylinder Volume in Gallons Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/cylinder-volume-gallons-calculator.
TG we-Calculate Editorial Team, "Cylinder Volume in Gallons Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/cylinder-volume-gallons-calculator
@misc{wecalculate_cylinder_volume_gallons_calculator, title = {Cylinder Volume in Gallons Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/cylinder-volume-gallons-calculator}}, year = {2026}, note = {TG we-Calculate} }
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