Volume of a Cylinder Calculator
Enter the radius and height of a cylinder and get its volume instantly — in cubic units plus liters and US gallons, which is what water tanks, propane cylinders and rain barrels are actually sold in. The formula V = πr²h is shown with your numbers in place, so the homework answer and the intuition both arrive together.
Cylinders are everywhere once you look: cans, pipes, wells, engines, candles. One formula covers them all.
How to use
- Enter the radius of the circular base and the height of the cylinder.
- Read the volume in cubic units, then in liters and US gallons for real-world capacity.
- Use diameter instead of radius by halving it first — the calculator works in radius.
Frequently asked questions
What is the formula for the volume of a cylinder?
V = πr²h: pi times the radius squared, times the height. A cylinder with a 5 cm radius and 10 cm height holds about 785 cubic centimeters (0.785 liters).
How many gallons is a 24-inch by 48-inch tank?
Radius 12 in, height 48 in: V = π × 144 × 48 ≈ 21,715 cubic inches ≈ 94 gallons. The calculator handles the cubic-inch-to-gallon hop when you work in inches.
Does diameter work instead of radius?
Yes, if you halve it first: a 20 cm diameter cylinder has a 10 cm radius. Entering the diameter as the radius overstates the volume by 4x - the most common mistake with this formula.
What is the volume of a cylinder in liters per cm of height?
That is the cross-sectional area: πr² cubic centimeters per centimeter of height. A 5 cm radius cylinder holds π × 25 ≈ 78.5 ml per centimeter - handy for rain gauges and graduations.