Tank Volume Calculator
Free tank volume calculator. Find the capacity in gallons and litres of a cylindrical, rectangular or capsule tank from its dimensions. For fuel, water and storage tanks.
About This Free Online Tank Volume Calculator
Our free tank volume calculator works out the capacity of a storage tank in gallons, litres and cubic feet from its dimensions. Choose a cylindrical, rectangular or capsule (round-end) tank and enter its size in inches — the tool instantly returns the total volume it holds. Perfect for sizing fuel oil tanks, water storage tanks, rain barrels, mixing tanks and aquariums. Every calculation runs in your browser with no signup, so you can check figures on site from any phone.
Features of Our Tank Volume Calculator
- Cylindrical, rectangular and capsule tank shapes
- Capacity in US gallons, litres and cubic feet
- Enter dimensions in inches — results update instantly
- Works for fuel, water, rain-harvesting and mixing tanks
- Capsule formula accounts for the domed round ends
- 100% client-side and private — no signup, no data sent
How to Use the Tank Volume Calculator
Using this tool is simple and requires no signup or registration. Follow these steps:
- Pick your tank shape — cylinder, rectangle or capsule.
- Enter the dimensions in inches (diameter, length, width and height as relevant).
- Read the capacity in gallons, litres and cubic feet.
- For a capsule, the height includes the two rounded ends.
Frequently Asked Questions About Tank Volume Calculator
How do you calculate the volume of a cylindrical tank?
For a vertical or horizontal cylinder, volume is π × radius² × length, where the radius is half the diameter. Enter the diameter and the cylinder length (or height) in inches and the calculator converts the result to gallons, litres and cubic feet automatically.
How many gallons are in a cubic foot?
One cubic foot holds about 7.48 US gallons (and about 28.3 litres). The calculator uses these exact conversions, so you can trust the gallon and litre figures.
What is a capsule tank?
A capsule tank is a cylinder with a hemisphere on each end. Its volume is the cylinder part π × radius² × (total height − diameter) plus the sphere (4/3) × π × radius³. Enter the full height including the domed ends.
Does this work for horizontal tanks too?
Yes. A horizontal cylinder has the same total capacity as a vertical one of the same diameter and length — π × radius² × length. This calculator gives the full (100% full) capacity of each shape.
Is this tank volume calculator free?
Yes, completely free with no signup. Every calculation runs in your browser, so your tank measurements never leave your device.
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