Cone Surface Area Calculator
Work out the total and lateral surface area of a cone from its radius and height or slant height free in your browser with this cone area calculator.
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Shape
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How to use this calculator
- Enter the radius and slant height.
- Press Calculate.
How it works
Total surface area = π × radius × (radius + slant height).
Worked example
radius 3 m, slant 5 m. ≈ 75.4 m².
Common mistakes
- Using the vertical height as the slant height — slant height l = √(r² + h²).
- Forgetting the base circle when total area is needed.
Frequently asked questions
How do I calculate a cone's surface area?
Total = πr² (base) + πrl (curved side) = πr(r + l), where l is the slant height √(r² + h²).
What is slant height?
The distance from the cone's tip down its sloping side to the base edge, found from the radius and vertical height with the Pythagorean theorem.
Related tools
- Cone Volume Calculator
- Sphere Surface Area Calculator
- Cylinder Surface Area Calculator
- Cube Surface Area Calculator
- Frustum Volume Calculator
- Hemisphere Volume Calculator
Explore more in Geometry, Shape, Area & Volume.
Cite this tool
Zerdly. (2026). Cone Surface Area Calculator. Retrieved from https://www.zerdly.com/tools/cone-surface-area-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.