Free · 3D geometry calculators 📦

Cylinder Curved Side Surface Area

Calculate a cylinder’s lateral area from height and radius or diameter, excluding the two circular ends.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A cylinder of radius 2 cm and height 10 cm has a curved-side area of 40π cm², approximately 125.663706 cm². Its circular top and bottom are excluded.

Lateral area = 2πrh = πdh; d = 2r

Worked example

Enter these known values and leave the other values blank.

Cylinder height
10 cm
Circular radius
2 cm
Circular diameter
4 cm
Curved side area
125.66 cm²

Assumptions and limitations

  • The model is a right circular cylinder with positive dimensions. It covers the curved side only.
  • Adding both circular ends would give total surface area 2πrh + 2πr². This calculator does not add those end areas.
  • Area and length units can be selected independently. A length conversion must be squared when converting area.

Common questions

Why does the curved surface use circumference times height?

Unrolling the cylindrical side forms a rectangle with width 2πr and height h. Multiplying these gives its area.

Can I use the diameter instead of the radius?

Yes. Enter the diameter and height; the radius is half the diameter, and lateral area is πdh.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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