Surface Area of a Cylinder: Formula and Examples
The surface area of a cylinder is SA = 2πr² + 2πrh, or 2πr(r + h). It is two circles plus the curved side.
3D Solids
Cylinder
A cylinder has two parallel circular bases joined by a curved surface. Unrolled, the curved surface is a rectangle 2πr wide.
- Volume
- V = πr2h
- Curved surface area
- CSA = 2πrh
- Total surface area
- TSA = 2πr(r + h)
- r radius
- h height
Unroll the can
- Top and bottom: two circles, 2 × πr².
- The curved side unrolls into a rectangle. Its width is the circumference 2πr and its height is h, so its area is 2πrh.
- Add them: SA = 2πr² + 2πrh.
Worked example
A can has radius 4 cm and height 10 cm.
- Circles: 2 × π × 4² = 100.53 cm²
- Curved side: 2 × π × 4 × 10 = 251.33 cm²
- Total: 351.86 cm²
Open-top cylinders
A cup has no lid, so use one circle: SA = πr² + 2πrh. For r = 4, h = 10: 301.59 cm².
Live calculator
Try the cylinder calculator
Try it yourself
How much paper covers the curved side of a tube with radius 3 cm and length 20 cm?
Show the answer
2 × π × 3 × 20 = 120π = 376.99 cm²
For volume, see our volume of a cylinder formula guide and the cylinder formulas page.
Surface area of a cylinder: FAQ
What is the surface area of a cylinder?
SA = 2πr(r + h): two circles plus the curved side.
What is the curved surface area?
CSA = 2πrh, the side only.
How do I find the surface area of an open cylinder?
Use one circle instead of two: SA = πr² + 2πrh.