Cylinder Volume Using Radius
The radius is the distance from the center of the circular base to its edge. Pair it with the cylinder's height and this calculator applies V = πr²h to give you the volume instantly. This is the most direct way to find cylinder volume.
Volume Using Radius
The Standard Radius Formula
V = π × r² × h is the foundation of every cylinder volume calculation. Here r is the radius of the circular base and h is the perpendicular height.
The formula works in two steps. First, r² gives the squared radius, and multiplying by π converts it into the area of the circular base (πr²). Second, multiplying that area by h stacks the circle through the full height, filling the 3D space.
Example: r = 7 cm, h = 15 cm. V = π × 49 × 15 = 2,309.07 cm³.
How to Find the Radius
If you can access the circular face of the cylinder, measure from the center to the edge. That's the radius directly.
If you only have the diameter (the full width across), divide by 2. If you have the circumference (the distance around), divide by 2π (approximately 6.2832).
For irregular cylinders or ones you can't easily measure, wrap a string around the base to get the circumference, then convert: r = C / (2π).
Radius vs Diameter: Which to Use
The formula expects the radius, not the diameter. If you plug in the diameter by mistake, your result will be 4× too large.
In practice, many measuring tools give you the diameter. Calipers measure across the full width. Rulers placed across a circle measure the diameter. Always divide by 2 before using the formula.
Some formulas are written with diameter: V = (π × d² × h) / 4. Both are equivalent — use whichever matches your measurement.