What is the volume of a cylinder?
Enter the diameter and height and get the volume of a cylinder instantly, using V = π r² h — in cubic metres and litres. It handles a cylinder standing upright or lying on its side, and a partial fill for sizing a half-full tank. For example, a 1 m diameter × 2 m tall cylinder holds π × 0.5² × 2 = 1.571 m³, or about 1,571 litres.
That is the volume of a full cylinder 1 m across and 2 m tall. Lower the fill depth to size a partly-filled tank.
Volume = π × (diameter ÷ 2)² × height. A full cylinder holds the same volume upright or on its side; only a partial fill differs. Capacities use exact conversions (1 US gal = 3.785 L). This is pure geometry — not a code value or a product spec.
Common questions
- What is the formula for the volume of a cylinder?
- The volume of a cylinder is V = π r² h — pi times the radius squared, times the height. The radius is half the diameter, so if you know the diameter it is V = π × (diameter ÷ 2)² × height. For example, a 1 m diameter × 2 m tall cylinder is π × 0.5² × 2 = 1.571 m³ (1,571 litres). The calculator above does it for you and converts to litres.
- How do you calculate the volume of a cylinder in gallons or litres?
- First find the volume in cubic units with V = π r² h, then convert. One cubic foot is 7.48 US gallons; one cubic metre is 1,000 litres (1 US gallon = 3.785 litres exactly). The calculator gives you the capacity in gallons or litres automatically, so you can size a tank, a water butt or a pressure vessel without doing the conversion by hand.
- Does a cylinder on its side hold the same volume as one standing up?
- A completely full cylinder holds the same volume whichever way it sits — V = π r² h either way. The difference is a partial fill. An upright cylinder fills linearly: half the depth is half the volume. A cylinder on its side does not — at half depth it is exactly half full, but at a quarter of the depth it holds much less than a quarter, because the cross-section is a circular segment. Switch the calculator to “on its side” for the correct partial volume.
- How do I find the volume of a partly-filled tank?
- Enter the tank's diameter and length (or height), then set the fill depth to how deep the liquid is. For an upright tank the calculator uses V = π r² × depth; for a tank on its side it uses the exact circular-segment area of the wetted cross-section times the length. Both give the actual volume held at that level, in cubic units and in gallons or litres.
- What can I use a cylinder volume calculator for?
- Any round vessel or shape: water and fuel tanks, hot water cylinders, rain barrels, culverts and pipes, round concrete columns and piers, silos and grain bins, pools and hot tubs, and even a coffee tin. For a round concrete column you can read the cubic yards or cubic metres straight off; for a tank you get the gallons or litres it holds.
Want the full walk-through? Read the cylinder volume guide → Pouring a round column? Try the concrete calculator →
Reference & education only. Not professional, engineering, or code-compliance advice. Estimates are based on published model codes; local amendments and your Authority Having Jurisdiction (AHJ) govern. Always verify against the current adopted code and a licensed professional before doing work.
Last reviewed 2026-07.