Tank Volume Calculator — Litres & Gallons
Find the total capacity and filled volume of any tank — enter the shape and dimensions to get instant results in litres, US gallons, UK gallons, and cubic metres. Adjust the fill level to see how much liquid is currently in the tank.
Tank shape
cm
cm
%
Total volume of the tank when full
- 1
Base area × height
π × 30² × 80 = 226,194.67 cm³Volume of a cylinder: V = π × r² × h. - 2
Convert cm³ to litres
226,194.67 ÷ 1000 = 226.19
How does this calculator work?
Tank volume: use π r² h for cylinders, L × W × H for boxes, (4/3) π r³ for spheres — all in the same unit. Divide cm³ by 1000 for litres, by 3785 for US gallons. Set the fill percentage to see the current liquid volume, not just the capacity.
Formula
How this is calculated
Tank volume depends on the geometric shape of the container. A vertical cylindrical tank (the most common water or oil tank) uses the formula V = π × r² × h, where r is the interior radius and h is the interior height — both in the same unit. Multiplying gives the volume in cubic centimetres (cm³ when dimensions are in cm), which converts to litres by dividing by 1000.
A rectangular (box-shaped) tank simply multiplies the three interior dimensions: V = length × width × height. A spherical tank, common for pressurised gas storage, uses V = (4/3) × π × r³. All conversions use exact factors: 1 L = 1000 cm³; 1 US gallon = 3785.41 cm³; 1 UK imperial gallon = 4546.09 cm³.
Note: use the interior dimensions of the tank, not the outside dimensions — tank walls and insulation add to the outer size. The fill-level field lets you see how much liquid is in the tank right now without recalculating the total capacity.
Frequently asked questions
1 US gallon = 3.78541 litres, so divide the litres by 3.78541. The calculator shows both. Note that UK imperial gallons are larger: 1 UK gallon = 4.54609 litres.
A horizontal cylinder at 100% fill has the same total volume as a vertical cylinder with the same radius and length — use the vertical cylinder option and enter the cylinder length as the height. Partial fill of a horizontal cylinder is more complex (it requires integrating a circular segment) and is not supported here.
If the tank is close to one of the supported shapes, use the nearest approximation. For truly irregular shapes, you can measure volume empirically by filling from a known-volume container (e.g. a calibrated bucket) and counting how many fills it takes.
Also known as
TG we-Calculate Editorial Team. (2026). Tank Volume Calculator — Litres & Gallons [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/tank-volume-calculator
TG we-Calculate Editorial Team. "Tank Volume Calculator — Litres & Gallons." TG we-Calculate. 2026. https://we-calculate.com/calculator/tank-volume-calculator.
TG we-Calculate Editorial Team, "Tank Volume Calculator — Litres & Gallons," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/tank-volume-calculator
@misc{wecalculate_tank_volume_calculator, title = {Tank Volume Calculator — Litres & Gallons}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/tank-volume-calculator}}, year = {2026}, note = {TG we-Calculate} }
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