Water tank capacity calculator
Choose the tank shape and enter its inside dimensions in meters to see how many liters it holds.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter tank shape, length (rectangular, horizontal), width (rectangular), height (rectangular, vertical) and diameter (cylinder).
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Rectangular: length × width × height. Cylinder: π × (diameter ÷ 2)² × height or length. Liters = cubic meters × 1000.
Example
Inputs: Tank shape = Rectangular or cube, Length (rectangular, horizontal) = 2 m, Width (rectangular) = 1.5 m, Height (rectangular, vertical) = 1.5 m, Diameter (cylinder) = 1.2 m. Result: Capacity: 4,500 L; Cubic meters: 4.5 m³; US gallons: 1,188.8 gal.
Limits and caveats
- Use inside dimensions; wall thickness reduces the real capacity.
- Tanks with domed ends or bottoms hold slightly more than a plain cylinder.
Questions about this tool
How many liters are in a cubic meter?
One cubic meter is exactly 1,000 liters.
What does a 2 × 1.5 × 1.5 m tank hold?
Its volume is 4.5 m³, which is 4,500 liters.
How do I work out a round tank?
Multiply π by the radius squared and by the height; a 1.2 m wide, 1.5 m tall tank holds about 1,696 liters.