Cylinder Surface Area
Calculate the surface area of a cylinder from its radius and height.
Covering a cylinder
A cylinder's surface area is the total of its curved side plus its two circular ends. This calculates it from the radius and height, useful for anything from labelling a can to painting a tank to wrapping a tube.
Enter the radius and height to find the surface area.
Unrolling the cylinder
The neat way to understand a cylinder's surface area is to imagine unrolling it. The curved side, when unrolled flat, is simply a rectangle — its height is the cylinder's height, and its width is the circle's circumference, since that is the distance around. So the curved surface is just circumference times height, an easy rectangle once you see it that way. Add the two circular ends, each an ordinary circle's area, and you have the total. This unrolling trick turns a curved-surface problem into a flat one, which is exactly how a label wraps around a can or a sheet forms a tube. Understanding the surface as a rectangle plus two circles makes the formula something you can reconstruct rather than memorise, and explains why a taller can needs a proportionally larger label.
Questions & answers
How can I understand a cylinder's curved surface?
Imagine unrolling it into a rectangle — its width is the circle's circumference and its height is the cylinder's height, so the area is circumference times height.
What makes up the total surface area?
The unrolled curved side (a rectangle) plus the two circular ends, each an ordinary circle's area.
Is anything uploaded?
No. The calculation happens in your browser.